SPECIES: Galium aparine
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Walter Knight © California Academy of Sciences
A distributional map of stickywilly is accessible through Plants database.ECOSYSTEMS :
Northwest: In the Northwest, stickywilly is described in coniferous and deciduous forests, shrublands, and grassland communities.
Coniferous forests: Stickywilly is typical in mixed conifer/blueberry/American skunkcabbage (Vaccinium spp./Lysichiton americanus) habitats of southeastern Alaska. Typical conifers in this vegetation type include western hemlock (Tsuga heterophylla), mountain hemlock (T. mertensiana), Alaska-cedar (Chamaecyparis nootkatensis), Sitka spruce (Picea sitchensis), and shore pine (Pinus contorta var. contorta) . On Saturna Island, British Columbia, stickywilly occurs in habitats dominated by Douglas-fir (Pseudotsuga menziesii), western hemlock, and salal (Gaultheria shallon) . In other parts of southern British Columbia, ponderosa pine is the climax species in communities where stickywilly occurs . Stickywilly is also found in ponderosa pine (P. ponderosa) communities of Washington, Oregon, Idaho, and western Montana [115,168]. In the Puget Trough of Washington, stickywilly occurs in Douglas-fir-Pacific madrone/pink honeysuckle (Arbutus menziesii/Lonicera hispidula) and Douglas-fir-Pacific madrone/salal vegetation associations . In central Idaho, researchers encountered stickywilly in Douglas-fir/ninebark (Physocarpus malvaceus) and grand fir/big huckleberry (Abies grandis/Vaccinium membranaceum) habitats .
Deciduous and mixed forests: Stickywilly is present at frequencies of 81%-100% in Oregon white oak (Quercus garryana)-dominated sites in coastal British Columbia where blue wildrye (Elymus glaucus) is also common . On the southern portion of Waldron Island, Washington, a white oak/stickywilly woodland community type occurs on the southeastern slopes of Pt. Disney . In southwestern Oregon, stickywilly occurs with at least 50% constancy in Oregon white oak-Douglas-fir/poison-oak (Toxicodendron diversilobum), Port-Orford-cedar (C. lawsoniana)-western hemlock/western sword fern (Polystichum munitum), and California red fir-white fir/deer oak/sidebells wintergreen (Abies magnifica shatensis-A. concolor/Q. sadleriana/Orthilia secunda) communities . Stickywilly is also found in Oregon white oak-true mountain-mahogany (Cercocarpus montanus) vegetation types in southwestern Oregon . In green ash (Fraxinus pennsylvanica) woodlands of eastern Montana, stickywilly occurs at 11% frequency .
Shrub- and grassland communities: Stickywilly occurs in southeastern Oregon's common snowberry-rose (Symphoricarpos albus-Rosa spp.)  and in northern Idaho's bluebunch wheatgrass/Sandberg bluegrass (Pseudoroegneria spicata-Poa secunda) vegetation associations .
Southwest: A variety of southwestern environments and habitats is occupied by stickywilly.
Coniferous forests: Stickywilly is common in several redwood (Sequoia sempervirens)-dominated vegetation types on northern California's coasts. On intermediate elevation sites where the dominant understory species is dwarf Oregon-grape (Berberis nervosa), stickywilly occurrence is greatest. On low- and high-elevation sites where deer fern (Blechnum spicant) and Pacific madrone codominate, respectively, stickywilly is still present . Stickywilly is described in spruce-fir (Picea spp.-Abies spp.) communities in Utah . In northeastern Arizona, stickywilly occupies Tsegi Canyon's Douglas-fir dominated forests . Along southern Arizona's San Pedro River, stickywilly occupies riparian sites with saltcedar (Tamarix spp.), mule's fat (Baccharis salicifolia), and singlewhorl burrobrush (Hymenoclea monogyra) . Stickywilly is also found in pinyon-juniper (Pinus spp.-Juniperus spp.) communities of the Great Basin Desert [71,161].
Deciduous and mixed forests: In the oak (Quercus spp.) woodlands of California's North Coast Range, stickywilly occupies several communities identified by the presence of snowberry, orchardgrass (Dactylis glomerata), Columbian larkspur (Delphinium trolliifolium), Lewis' mockorange (Philadelphus lewisii), bladder-fern (Cystopteris spp.), Sierra gooseberry (Ribes roezlii), varileaf phacelia (Phacelia heterophylla), and dogstail grass (Cynosurus spp.) . Stickywilly in the Berkeley Hills, occurs in oak woodlands dominated by coast live oak (Q. agrifolia), bigleaf maple (Acer macrophyllum), California bay (Umbellularia californica), and poison-oak . In riparian areas of California's Central Valley, stickywilly is found among cottonwoods (Populus spp.), willows (Salix spp.), boxelder (A. negundo), California black walnut (Juglans californica), Douglas' sagewort (Artemisia douglasiana), and California manroot (Marah fabaceus) .
In the Sierra Nevada foothills, stickywilly occurs in chaparral communities where blue oak (Q. douglasii), gray pine (Pinus sabiniana), interior live oak (Q. wislizenii), and wedgeleaf ceanothus (Ceanothus cuneatus) are typical . In southern California's scrub oak (Q. berberidifolia) communities, stickywilly occurs with Eastwood manzanita (Arctostaphylos glandulosa) and chamise .
In Gambel oak (Q. gambelii)-dominated sites of central and northern Utah, stickywilly is common. Other associated species include chokecherry (Prunus virginiana), bigtooth maple (A. grandidentatum), mountain snowberry (S. oreophilus), Saskatoon serviceberry (Amelanchier alnifolia), cheatgrass (Bromus tectorum), Kentucky bluegrass (Poa pratensis), and bluebunch wheatgrass [80,114]. Stickywilly occurs in quaking aspen (Populus tremuloides)-dominated sites of Utah, too [68,161].
Shrub- and grassland communities: Stickywilly's presence in big sagebrush (Artemisia tridentata) communities is noted by several authors [71,114,161]. In Utah's Wasatch Mountains State Park, antelope bitterbrush (Purshia tridentata) and bluebunch wheatgrass are common sagebrush associates . In California's chaparral communities stickywilly is common. On Santa Cruz Island, stickywilly occurs in scrub oak chaparral, chamise (Adenostoma fasciculatum) chaparral, and hollyleaf cherry (Prunus ilicifolia) woodlands . Stickywilly is described in grass-forb habitat types in northern Utah with brome grasses (Bromus spp.), prairie Junegrass (Koeleria macrantha), and lupines (Lupinus spp.) .
North-central: Hardwood forests and prairies of the north-central U.S. are typical stickywilly habitat.
Deciduous forests: In the bur oak/eastern hophornbeam (Q. macrocarpa/Ostrya virginiana) habitat type of the Great Plains Province, stickywilly has 75% constancy . In southern Wisconsin, stickywilly occurs with sugar maple (Acer saccharum), slippery elm (Ulmus rubra), American elm (U. americana), and basswood (Tilia americana) . Stickywilly is typical of forests adjacent to river systems or wet meadows where sugar maple, American hornbeam (Carpinus caroliniana), northern spicebush (Lindera benzoin), eastern hophornbeam, yellow-poplar (Liriodendron tulipifera), northern red oak (Q. rubra), white oak (Q. alba), bur oak, shagbark hickory (Carya ovata), shellbark hickory (C. laciniosa), ash (Fraxinus spp.), eastern redcedar (Juniperus virginiana), elm (Ulmus spp.) and/or basswood may characterize the overstory vegetation [73,76,77,146]. Associated forbs and shrubs may include false lily-of-the-valley (Maianthemum racemosum ssp. racemosum), snow trillium (Trillium grandiflorum), sweet cicely (Osmorhiza claytonii), poison-ivy (Toxicodendron radicans), trumpet creeper (Campsis radicans), Canadian woodnettle (Laportea canadensis), and bristly buttercup (Ranunculus hispidus var. nitidus) [76,146] On floodplains where stickywilly also occurs, boxelder, cottonwood, willow, hackberry (Celtis spp.) and walnut (Juglans spp.) are typical .
Grassland communities: In Jasper County, Illinois, stickywilly occurs in a tallgrass prairie dominated by big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), and showy partridgepea (Cassia fasciculata) . Stickywilly is considered a "characteristic forb" in a moist switchgrass (Panicum virgatum) community type with big bluestem, bluegrasses (Poa spp.), and Scribner's rosette grass (Dichanthelium oligosanthes var. scribnerianum) .
In the south-central
U.S., stickywilly is commonly described in hardwood bottomland forests.
Along the Trinity River of Texas, stickywilly occurs with an overstory of winged elm (U. alata), post oak (Q. stellata), and Mexican plum (Prunus mexicana). The understory is Virginia creeper (Parthenocissus quinquefolia) and saw greenbrier (Smilax bona-nox) . On the Mississippi floodplain in southern Louisiana, stickywilly is found in bottomland hardwood-baldcypress (Taxodium distichum) forests. The dominant overstory species are sugarberry (Celtis laevigata), green ash, and sweetgum (Liquidambar styraciflua) .
Northeast: Stickywilly is described in northeastern hardwood forests, meadows, and abandoned fields.
Mixed forests: Riparian areas and floodplains typically contain stickywilly. In north-central Ohio, stickywilly occurs in old-growth mixed oak-hickory (Carya spp.) floodplain forests and in upland riparian forests dominated by beech (Fagus spp.) and maple (Acer spp.) . In the Lake Agassiz Peatlands of north-central Minnesota stickywilly occurs in rich swamp forests. Northern white-cedar (Thuja occidentalis), black ash (Fraxinus nigra), tamarack (Larix laricina), and white spruce (Picea glauca) are characteristic species in swamp forests where stickywilly is present with low coverages . Stickywilly was a major understory species in oak-sugar maple forests of southwestern Ohio where both white and northern red oak occur. Stickywilly frequency was lowest in the youngest stands (40-year-old), where water content and light levels were lowest . On the floodplains of the Potomac River (Maryland side) stickywilly occurs with an overstory of boxelder, pawpaw (Asimina triloba), hackberry (Celtis occidentalis), northern spicebush, and sycamore (Platanus occidentalis) .
Meadow communities: Stickywilly is described in wet meadows of Quebec's Huntingdon Marsh near the Ontario and New York borders. Also typical are bluejoint reedgrass (Calamagrostis canadensis), sedges (Carex spp.), and common marsh bedstraw (Galium palustre) .
Old fields and urban communities: In the abandoned fields of central and western New York, stickywilly is present with several shrubs including Morrow's honeysuckle (Lonicera morrowii), gray dogwood (Cornus racemosa), red-osier dogwood (C. sericea), and silky dogwood (C. amomum). Common forbs and grasses include Canada goldenrod (Solidago canadensis), timothy (Phleum pratense), quackgrass (Elymus repens), and Canada bluegrass (Poa compressa) . In the Wave Hill natural area in Bronx, New York, stickywilly persists in open woodland interspaces with a variety of nonnative vegetation including Amur peppervine (Ampelopsis brevipedunculata), Amur honeysuckle (L. maackii), garlic mustard (Alliaria petiolata), and Japanese knotweed (Polygonum cuspidatum) .
Southeast: Stickywilly is typical of southeastern riparian and floodplain forests.Deciduous forests: In northern Kentucky mixed mesophytic forests, sugar maple, white ash (Fraxinus americana), sycamore, boxelder, and northern spicebush provide the canopy for stickywilly . Sweetgum, yellow-poplar, ash, elm, and northern red maple commonly occur with stickywilly in bottomland mixed hardwood forests in the Piedmont of North Carolina .
© 2005 Keir Morse
© 2004 Carol W. Witham
GENERAL BOTANICAL CHARACTERISTICS:
This description provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available [11,25,41,57,58,65,71,94,129,158,161,165,167].
Stickywilly is an annual forb [25,44,58,143] that due to its highly plastic nature can grow as a winter or summer annual in temperate regions . Under certain environmental conditions, stickywilly may grow more like a biennial . The stickywilly root system is a shallow, branching taproot. Stickywilly has weak square stems with few branches [25,41,44,58]. Weak stems give stickywilly a gangly appearance, and tangles of stickywilly's scrambling stems with nearby vegetation are inevitable [44,143]. This growth form allows stickywilly a spread of up to 6 feet (1.8 m) . At the stem angles are hooked hairs or bristles that further aid in clambering and provide for plant dispersal [21,41,44].
A distinct characteristic of bedstraw species (Galium spp.) is leaves arranged in whorls. Stickywilly typically displays simple linear leaves (0.4 to 3.2 inches long (1-8 cm)) in whorls of 8. However, whorls of 6 and 7 leaves occur as well [25,41,44,58,62,143]. Flowers are perfect cymes and fruits are schizocarps that measure between 1-4 mm in diameter, but 3-4 mm is more typical [44,57,143]. Seeds are covered with sticky hooked hairs [21,25,58]. When found on dry sites, stickywilly leaves measure 0.4 to 1.6 inches (1-4 cm) long, and fruits typically range from 1.5 to 3 mm in diameter .
Look-alike species: Stickywilly can be mistaken with Marin County bedstraw (Galium spurium) especially when found in crops or disturbed sites. Marin County bedstraw is a more aggressive, nonnative species tolerant of dry sunny areas. The 2 species are unreliably distinguished by habitat, but chromosome numbers distinguish them .RAUNKIAER  LIFE FORM:
Breeding system: Stickywilly produces perfect flowers [53,62] and is largely self-pollinating [28,62,103].
Pollination: In a review article, DeFelice  indicates that insects may pollinate stickywilly, and others  infrequently observed small bees and flower flies visiting stickywilly flowers.
Seed production: The information regarding seed production by stickywilly varies widely. A single stickywilly plant in North Dakota of average size, growing with little "competition" from other vegetation, produced 105 seeds . Royer and Dickinson  suggest that 1 plant can yield 400 seeds. Likewise in a review, DeFelice  reports 300 to 400 seeds produced per plant. In old fields of Tennessee, researchers compared the stickywilly seed rain in sassafras (Sassafras albidum) stands in different successional stages. In 5-15 year-old-stands, an estimated 22,000 stickywilly seeds/ha were collected on the ground. In stands over 50 years old, 81,000 seeds/ha were trapped on the ground, and 1,160,000 seeds were recovered from airborne collectors. No data were provided on stickywilly coverage in the study sites or distances from the trapping area .
Seed dispersal: Stickywilly is highly adapted for long-distance dispersal. The hooked bristles coating stickywilly seed easily attach to feathers, fur, and clothing [28,62,143,158]. The backward-turned bristles on leaves and stems also grip easily to animals, equipment, and clothing aiding in long-distance dispersal of this species . DeFelice  reports in a review that stickywilly seeds are light enough for wind dispersal and can float due to empty space between the 2 carpels.
In northern Delaware and southern Pennsylvania, researchers calculated migration rates for stickywilly based on plant distances from an old-growth ecotone to the furthest plant or to the furthest occurrence where plants grew at 1/2 peak density. Stickywilly's migration rates were 2.48 ± 0.71 m/year and 1.94 ± 0.30 m/year based on the furthest 1/2 peak density and furthest individual calculations, respectively. These high dispersal rates are likely the result of animal transport .
Seed banking: Estimates regarding amounts of seed banked and duration of seed viability in the soil for stickywilly are broad ranging. Royer and Dickinson  suggest stickywilly seed can retain viability for 6 years. After reviewing literature on this subject, DeFelice  indicates that seeds are viable in the soil for just 2 to 3 years.
In Pennsylvania, the existing vegetation and soil seed bank were compared in forested, prairie, and prairie edge sites. Stickywilly was present in 1 of the forested plots dominated by black walnut (Juglans nigra), black cherry (Prunus serotina), eastern white pine (Pinus strobus), and hawthorn (Crataegus spp.), but no stickywilly seed germinated in soil collected from any of the 3 sites . In Douglas-fir and grand fir forests of central Idaho where stickywilly occurred with 0%-6% constancy, researchers recovered only 2 viable seeds from 20 soil samples collected from early May to late August . Soil samples taken from ponderosa pine/common snowberry habitat types in southeastern Washington produced high stickywilly seed density estimates. In the area, stickywilly occupied 1% coverage and was 83% constant. From soil cores samples germinated at optimal conditions, researchers estimated 83 ± 169 seeds/m² and 417±225 seeds/m² in spring and fall soils, respectively. Seed densities were greatest in the litter layer .
Germination: Seed germination percentages are reduced by increased depth of burial and increased temperatures. Stickywilly seed requires burial to germinate. Germination in a laboratory setting was between 0% and 5% when seed was uncovered, but when buried at depths of between 2 and 10 mm, 60%-80% of seed germinated . When buried 3.9 inches (10 cm) below the soil surface, 5%-15% of seed germinated, and no seedlings emerged at 4.7 inches (12 cm) . Royer and Dickinson  claim that no seedlings emerge when seed is buried greater than 1.6 inches (4 cm) deep. In a review, Holm and others  suggest that seed will not germinate from depths of 1.6 inches (4 cm) when in heavy, firm soils, and when buried 3.9 inches (10 cm) deep in light soils, germination, flowering, and fruiting are delayed.
In the laboratory, Pratt and others  found that heat treatments significantly (p<0.05) reduced germination of stickywilly. Of 196 fall collected seeds, just 21 seeds germinated after being heated at 167 °F (75 °C) for 20 minutes then stratified at 32 °F (0 °C) for 60 days. No seeds survived a heat treatment of 212 °F (100 °C) for 20 minutes followed by cold stratification. The researchers concluded that fire likely kills stickywilly seed in the litter layer . Royer and Dickinson  report decreased germination when soil temperatures are above 68°F (20 °C).
Holm and others  report recovering viable seed from cattle, horse, pig, goat, and bird feces, while other reviewers, Malik and Vanden Born , describe increased germination percentages following animal digestion.
Seedling establishment/growth: Stickywilly develops rapidly. Root lengths may be 2 to 2.4 inches (5-6 cm) long by the time 1st leaves appear, and flowers can appear 8 weeks after germination . Seedlings may also appear throughout the growing season .
Studies in southwestern Ohio reveal that 79%-94% of seedlings survived to reproductive age planted on mixed northern red oak, hickory, sugar maple, and ash forests where the density of Amur honeysuckle ranged from 0.3-0.7 shrub/m² .
In a greenhouse, researchers compared the growth of stickywilly seed collected from Ontario, Illinois, Oklahoma, and California. Growth rate differences were apparent 6 weeks after planting done in August. Developmental differences in seeds of different localities are shown below :
|Seed source||Oklahoma||Ontario and California||IL|
|Height by late December||3.28 ft (1 m)||intermediate between Oklahoma and Illinois||6-7.9 inches (150-200 mm)|
|Flowering date||late December||early March||late January|
Asexual regeneration: Malik and Vanden Born  indicate that stickywilly does not reproduce vegetatively.SITE CHARACTERISTICS:
Climate: The ability to behave as a winter or summer annual  allows stickywilly a broad range of climatic tolerances. The climate patterns for several regions in which stickywilly occurs are provided below:
|Region||Summer max. and winter min. temp.||Annual precipitation||Other|
|Eastern Montana ||88-0.4 °F||11.4-16.1 inches||semiarid, continental climate|
|Wasatch Mts., northern Utah ||61-27 °F||15.4 inches||70-80 consecutive frost-free days|
|Northeastern Arizona ||100-55 °F||6.8-18.8 inches||semiarid to arid continental climate|
|Northern California ||100-19 °F||70.1-80 inches||Mediterranean climate, receives 90% of precipitation from Oct.-May|
|New York, Ontario and Quebec borders ||90 to -44 °F||39.8 inches,
includes 90.2 inches snowfall
|rainfall delivery consistent|
|North-central Ohio ( and references therein).||69-27 °F|| 35.4 inches,
snowfall 36 inches
|humid continental climate, 60% of precipitation falls from April-Sept.|
Elevation: Several western states reported elevational ranges for stickywilly:
|Arizona||Grand Canyon||1,201 to 7,999 feet (366-2,438 m) |
|California||southern||up to 7,500 feet (2,286 m) |
|Colorado||western||5,000 to 9,500 feet (1,524-2,896 m) |
|Montana||west-central||below 6,004 feet (1,830 m) |
|Nevada||5,400 to 7,500 feet (1,646-2,286 m) |
|New Mexico||5,000 to 9,000 feet (1,524-2,742 m) |
|Utah||3,002 to 10,007 feet (915-3,050 m) |
Soils: Stickywilly favors moist soils and tolerates sites with moderate to poor drainage . Rich loam, heavy organic soils with above average nitrogen and phosphorus content, and pH values between 5.5 and 8.0 are reportedly preferred in reviews [28,56,90].
In a Minnesota swamp forest where northern white-cedar, black ash, tamarack, and white spruce are common, stickywilly occurrence was indicative of minerotrophic conditions, a pH range between 5.8 and 7, and calcium contents of 10 to 25 ppm . In bottomlands of New York's north shore of Long Island, researchers compared the soil and vegetation composition in 1922 and 1985. In 1922, soil pH ranged from 6 to 7 and stickywilly was present, yet sites revisited and surveyed in 1985 had a pH of 4.1 and were without stickywilly. Researchers considered increased soil acidity the reason that stickywilly was unable to occupy the site .SUCCESSIONAL STATUS:
Shade relationships: Habitats providing light shade are preferred by stickywilly; however, deep shade and/or full sun conditions are tolerated in some environments. In greenhouse simulations, stickywilly root and shoot growth were significantly lower (p<0.001) under deep shade conditions. Height increases were greater under patchy light conditions than under deep shade . In central California, stickywilly produced more biomass when growing under live or dead blue oaks than when growing in open grasslands. The density of stickywilly was 1.3 g/m² under live trees, 2.0 g/m² growing under dead trees, and 0.2 g/m² in open grassland .
Comparisons between Douglas-fir forests of western Washington and Oregon revealed that stickywilly coverage and frequency were 0.2% and 20.8%, respectively, in forests characterized by well-spaced Douglas-fir trees between 21.6 and 25.6 inches (55-65 cm) dbh. Stickywilly was absent from forests with closely-spaced Douglas-fir trees between 11.8 and 17.7 inches (30-45 cm) dbh. .
Pyle  made comparisons between Maryland's Potomac River floodplain forests with different levels of shading and human use. The canopy of these floodplain forests were dominated by box elder and pawpaw. Stickywilly was present only on sites receiving the heaviest recreation use and the highest degree of shading. Stickywilly did not occur on sites with little to no human disturbance that received mid-levels of sunlight. The combined land use and shading variables make determining the most important factor affecting stickywilly presence impossible .
Recent disturbances/early succession: The following studies suggest that stickywilly is not necessarily encouraged through disturbances and that disturbance responses are likely situation dependent. Stickywilly was not present in 1-, 2-, or 3-year-old abandoned fields of Piedmont, North Carolina, but did occur in bottomland mixed-hardwood forests in the same area . In western Massachusetts, stickywilly occurred on marshes above the active flood plain but did not occur on annually flooded sites . In north-central Idaho, stickywilly was absent from the earliest seral communities within a western redcedar-western hemlock vegetation association . Following the excavation of hardwood bottomland forests near Dallas, Texas, Nixon  monitored early successional changes. Stickywilly was absent from the youngest sites (3 and 5 years since excavation) and had an importance value of 1 on sites excavated 47 years prior. The 3-, 5-, and 47-year-old forests were dominated by eastern cottonwood (Populus deltoides), black willow (Salix nigra), and sugarberry, respectively. On unexcavated forest sites, stickywilly had an importance value of 20 . On a debris flow along a second order stream in the Central Coast Range of Oregon, stickywilly presence was first recorded 7 years following the initiation of succession. Stickywilly was absent from sites visited 10 years following the debris flow .
In an Oregon white oak meadow of southwestern British Columbia, MacDougall  intentionally disturbed sites in an attempt to decrease nonnative species. Disturbances included burning, mowing, and removal of nonnative species. Some sites were treated in the fall, others in the summer and fall. All treated sites were grouped and considered disturbed, so differences between burning, mowing, or removal treatments were lost. On shallow soil sites (2 to 5.9 inches (5-15 cm)), the predisturbance coverage of stickywilly was 9.8% and postdisturbance coverage was 22.6%. On deep soil sites (>39.4 inches (100 cm)), the predisturbance and postdisturbance coverages of stickywilly were 2.5% and 2.3%, respectively .
Following a 1975 clearcut and slash burn in north-central California, McDonald  monitored early succession in a ponderosa pine community. Stickywilly was absent in the 1st, 3rd, and 4th posttreatment years and frequency was low in the 2nd and 5th posttreatment years. The percent frequency, density, and height (average of 3 tallest stems) of stickywilly are given below for all posttreatment monitoring years. Sites were exceptionally dry in 1976 and 1977 and were extremely wet in 1978 .
|Year||Frequency (%)||Density (plants/milacre)||Height (ft)|
Past disturbances/later succession: Stickywilly occupies developing, mature, and old-growth woodlands and forests but is generally more frequent in mid-successional stages. In Douglas-fir forests of Oregon's Cascade Range, stickywilly's frequency of occurrence was significantly greater (p<0.1) in mature (80-195 year-old-forests) than in old-growth (≥195 years) or young (<80 years) forests . In coast live oak woodlands of Berkeley Hills, California, stickywilly frequency was 5% to 52%, while frequency was 1% to 9% in San Francisco Bay woodlands considered successionally older . In a southeastern Washington ponderosa pine/common snowberry community representative of a middle stage of succession, stickywilly had 83% constancy and 1% cover .
Luken and Fonda  investigated changes in vegetation, canopy cover, and soil nitrogen as red alder (Alnus rubra) stands aged along the Hoh River in Washington. Soil nitrogen content increased and canopies became more open with age. Stickywilly frequency and cover were greatest in the 24-year-old red alder stands. The differences in stickywilly coverage and frequency in 14-, 24-, and 65-year-old red alder stands are presented below :
|Stand Age (years)||14||24||65|
In mature American beech-sugar maple forests of southwestern Ohio, canopy gaps were created by falling single American beech trees. Vegetation changes in different aged gaps (1-15 years) were monitored. The middle-aged gaps had significantly (p=0.05) greater coverage of stickywilly. The results are provided below; values followed by the same letter are not significantly different .
|Gap age (years)||1-2||5-7||12 & 15||Intact canopy|
|Stickywilly coverage (average)||0.4a||0.5b||0.4a||0.4a|
|California (southern)||March-July |
|Canada||late May-mid-June |
|Great Plains||May-August |
|Gulf and Atlantic coasts||April-July |
|Illinois (Jasper County)||1st flowers: mid-May|
|peak flowering: late May|
|last flowers_ mid-June |
|Illinois (southeast)||mid-April-mid June |
|New Mexico||June-September |
|North and South Carolina||July-August |
|North Dakota||flowering begins as early as May 21 or as late as June 13 |
|Texas (lower Rio Grande Valley)||May-June |
|Texas (north-central)||March-April |
|Utah (Wasatch Mts.)||mid-May-late June |
|Virginia (Blue Ridge Mts.)||April-May |
|West Virginia||April-June |
Fire regimes: Many diverse communities provide stickywilly habitat. The fire regimes are dictated by the overstory community. Stickywilly experiences extreme ranges in fire frequencies. Vegetation in Quebec's Huntingdon Marsh that includes stickywilly burns almost every fall or early spring. Researchers found evidence of previous growing season fires in 28% to 50% of the quadrats sampled, and 14% to 25% of quadrats burned in the last 2 or 3 years . Western Montana's rough fescue (Festuca altaica)-dominated grasslands that are also stickywilly habitat tolerate fire frequencies of between 5 and 10 years. Researchers based estimated fire frequencies on this community's postfire vegetation recovery . In the East, stickywilly is common in sugar maple communities where fires are exceptionally rare, occurring at greater than 1,000-year intervals . This range of fire regimes tolerated by stickywilly suggests that this species is fire tolerant but not fire dependent.
The following table provides fire return intervals for plant communities and ecosystems where stickywilly is important. For further information, see the FEIS review of the dominant species listed below. This list may not be inclusive for all plant communities in which stickywilly occurs. If you are interested in plant communities or ecosystems that are not listed below, see the complete FEIS fire regime table.
|Community or Ecosystem||Dominant Species||Fire Return Interval Range (years)|
|silver fir-Douglas-fir||Abies amabilis-Pseudotsuga menziesii var. menziesii||> 200|
|grand fir||Abies grandis||35-200 |
|maple-beech-birch||Acer-Fagus-Betula spp.||> 1,000|
|silver maple-American elm||Acer saccharinum-Ulmus americana||< 35 to 200|
|sugar maple||Acer saccharum||> 1,000|
|sugar maple-basswood||Acer saccharum-Tilia americana||> 1,000 |
|California chaparral||Adenostoma and/or Arctostaphylos spp.||< 35 to < 100 |
|bluestem prairie||Andropogon gerardii var. gerardii-Schizachyrium scoparium||< 10 [78,111]|
|Nebraska sandhills prairie||Andropogon gerardii var. paucipilus-Schizachyrium scoparium||< 10|
|bluestem-Sacahuista prairie||Andropogon littoralis-Spartina spartinae||< 10 |
|silver sagebrush steppe||Artemisia cana||5-45 [55,117,169]|
|sagebrush steppe||Artemisia tridentata/Pseudoroegneria spicata||20-70 |
|basin big sagebrush||Artemisia tridentata var. tridentata||12-43 |
|mountain big sagebrush||Artemisia tridentata var. vaseyana||15-40 [6,20,100]|
|Wyoming big sagebrush||Artemisia tridentata var. wyomingensis||10-70 (40**) [156,172]|
|coastal sagebrush||Artemisia californica||< 35 to < 100 |
|plains grasslands||Bouteloua spp.||< 35 [111,169]|
|cheatgrass||Bromus tectorum||< 10 [112,162]|
|California montane chaparral||Ceanothus and/or Arctostaphylos spp.||50-100 |
|sugarberry-America elm-green ash||Celtis laevigata-Ulmus americana-Fraxinus pennsylvanica||< 35 to 200 |
|mountain-mahogany-Gambel oak scrub||Cercocarpus ledifolius-Quercus gambelii||< 35 to < 100 |
|beech-sugar maple||Fagus spp.-Acer saccharum||> 1,000|
|black ash||Fraxinus nigra||< 35 to 200 |
|juniper-oak savanna||Juniperus ashei-Quercus virginiana||< 35|
|Ashe juniper||Juniperus ashei||< 35|
|western juniper||Juniperus occidentalis||20-70|
|Rocky Mountain juniper||Juniperus scopulorum||< 35 |
|cedar glades||Juniperus virginiana||3-22 [50,111]|
|tamarack||Larix laricina||35-200 |
|western larch||Larix occidentalis||25-350 [5,13,27]|
|yellow-poplar||Liriodendron tulipifera||< 35 |
|Great Lakes spruce-fir||Picea-Abies spp.||35 to > 200|
|northeastern spruce-fir||Picea-Abies spp.||35-200 |
|southeastern spruce-fir||Picea-Abies spp.||35 to > 200 |
|Engelmann spruce-subalpine fir||Picea engelmannii-Abies lasiocarpa||35 to > 200 |
|black spruce||Picea mariana||35-200|
|conifer bog*||Picea mariana-Larix laricina||35-200 |
|pinyon-juniper||Pinus-Juniperus spp.||< 35 |
|Rocky Mountain lodgepole pine*||Pinus contorta var. latifolia||25-340 [12,13,147]|
|Sierra lodgepole pine*||Pinus contorta var. murrayana||35-200 |
|shortleaf pine||Pinus echinata||2-15|
|slash pine-hardwood||Pinus elliottii-variable||< 35|
|longleaf pine-scrub oak||Pinus palustris-Quercus spp.||6-10 |
|Pacific ponderosa pine*||Pinus ponderosa var. ponderosa||1-47 |
|interior ponderosa pine*||Pinus ponderosa var. scopulorum||2-30 [4,10,83]|
|Arizona pine||Pinus ponderosa var. arizonica||2-15 [10,24,128]|
|eastern white pine||Pinus strobus||35-200|
|eastern white pine-eastern hemlock||Pinus strobus-Tsuga canadensis||35-200|
|eastern white pine-northern red oak-red maple||Pinus strobus-Quercus rubra-Acer rubrum||35-200|
|Virginia pine||Pinus virginiana||10 to < 35|
|Virginia pine-oak||Pinus virginiana-Quercus spp.||10 to < 35|
|sycamore-sweetgum-American elm||Platanus occidentalis-Liquidambar styraciflua-Ulmus americana||< 35 to 200 |
|eastern cottonwood||Populus deltoides||< 35 to 200 |
|aspen-birch||Populus tremuloides-Betula papyrifera||35-200 [31,159]|
|quaking aspen (west of the Great Plains)||Populus tremuloides||7-120 [4,47,99]|
|black cherry-sugar maple||Prunus serotina-Acer saccharum||> 1,000 |
|mountain grasslands||Pseudoroegneria spicata||3-40 (10**) [3,4]|
|Rocky Mountain Douglas-fir*||Pseudotsuga menziesii var. glauca||25-100 [4,6,7]|
|coastal Douglas-fir*||Pseudotsuga menziesii var. menziesii||40-240 [4,104,121]|
|California mixed evergreen||Pseudotsuga menziesii var. menziesii-Lithocarpus densiflorus-Arbutus menziesii||< 35|
|California oakwoods||Quercus spp.||< 35 |
|oak-hickory||Quercus-Carya spp.||< 35 |
|oak-juniper woodland (Southwest)||Quercus-Juniperus spp.||< 35 to < 200 |
|northeastern oak-pine||Quercus-Pinus spp.||10 to < 35 |
|oak-gum-cypress||Quercus-Nyssa-spp.-Taxodium distichum||35 to > 200 |
|southeastern oak-pine||Quercus-Pinus spp.||< 10 |
|coast live oak||Quercus agrifolia||2-75 |
|white oak-black oak-northern red oak||Quercus alba-Q. velutina-Q. rubra||< 35 |
|canyon live oak||Quercus chrysolepis||<35 to 200|
|blue oak-foothills pine||Quercus douglasii-P. sabiniana||<35 |
|northern pin oak||Quercus ellipsoidalis||< 35 |
|Oregon white oak||Quercus garryana||< 35 |
|bear oak||Quercus ilicifolia||< 35 |
|California black oak||Quercus kelloggii||5-30 |
|bur oak||Quercus macrocarpa||< 10 |
|oak savanna||Quercus macrocarpa/Andropogon gerardii-Schizachyrium scoparium||2-14 [111,159]|
|chestnut oak||Quercus prinus||3-8|
|northern red oak||Quercus rubra||10 to < 35|
|post oak-blackjack oak||Quercus stellata-Q. marilandica||< 10|
|black oak||Quercus velutina||< 35|
|live oak||Quercus virginiana||10 to< 100 |
|interior live oak||Quercus wislizenii||< 35 |
|blackland prairie||Schizachyrium scoparium-Nassella leucotricha||< 10|
|Fayette prairie||Schizachyrium scoparium-Buchloe dactyloides||< 10 |
|little bluestem-grama prairie||Schizachyrium scoparium-Bouteloua spp.||< 35 |
|redwood||Sequoia sempervirens||5-200 [4,37,142]|
|baldcypress||Taxodium distichum var. distichum||100 to > 300|
|pondcypress||Taxodium distichum var. nutans||< 35 |
|western redcedar-western hemlock||Thuja plicata-Tsuga heterophylla||> 200 |
|eastern hemlock-yellow birch||Tsuga canadensis-Betula alleghaniensis||> 200 |
|western hemlock-Sitka spruce||Tsuga heterophylla-Picea sitchensis||> 200|
|mountain hemlock*||Tsuga mertensiana||35 to > 200 |
|elm-ash-cottonwood||Ulmus-Fraxinus-Populus spp.||< 35 to 200 [31,159]|
Coniferous forests: The following studies indicate that stickywilly is often absent from the 1st postfire year conifer communities. Several fires burned in 2 northeastern Oregon forests (Douglas-fir and subalpine fir) where stickywilly occurs. Moderately severe fires partially consumed the litter and woody debris, blackened shrub stems, and charred and partially burned tree trunks. Severe fires deeply charred tree trunks, consumed most branches, consumed litter and duff, and left a white ash layer. Stickywilly coverage in the 5th postfire year surpassed prefire coverages in moderate and severe burns. Pre- and postfire percent coverages for stickywilly are provided below :
|Vegetation association||prefire||postfire year 1||postfire year 5||prefire||postfire year 1||postfire year 5|
moderate burn (n=4)
severe burn (n=2)
|Subalpine fir/menziesia (Menziesia ferruginea)||
partial burn (n=2)
severe burn (n=2)
A study of different-aged burns in western hemlock-Douglas-fir forests in the Olympic Mountains of Washington revealed stickywilly's preference for recently disturbed forests. The author described past fires as "catastrophic," but no additional information regarding fire season or severity was given. The percent frequency of stickywilly is shown below :
|Time since fire (years)||2||3||19||110||515|
Deciduous forests: Reestablishment of stickywilly following fires in deciduous woodlands is quick. In a red alder woodland in the Oregon Coast Range, sites were clearcut in early spring (March-April), treated with herbicide in June, and burned in early August. The prefire frequency of stickywilly was 15%. Two months following treatments frequency of stickywilly was 0%, and 4 months later stickywilly frequency was 1% .
"Moderately disturbed" upland slippery elm-dominated forests of northern Illinois burned during the 1992 dormant and growing seasons. The dormant season fire burned in March when temperatures averaged 62 °F (16.7 °C), relative humidity was 70%, and the 8 days prior received no precipitation. Approximately 75% to 80% of the unit burned, flame heights measured between 5.9 and 39.4 inches (15-100 cm), and fire spread was 1.3 m/minute. The growing season fire burned in May when temperatures averaged 78 °F (25.6 °C), relative humidity was 29%, and the 9 days prior received no precipitation. Approximately 75%-80% of the unit burned, flame heights were between 4 and 29.5 inches (10-75 cm), and fire spread was 1.7 m/minute. The density of stickywilly decreased on all burned and unburned sites in 1992 and 1993. Stickywilly had not recovered on either burned site by the 3rd postfire year. The prefire and postfire stem densities (per m²) of stickywilly on dormant season burns, growing season burns, and unburned plots are provided below .
|Fire season||dormant (March)||growing (May)||unburned|
|1992||1993||1994||1991 (prefire)||1992||1993||1994||1991 (prefire)||1992||1993||1994|
|Stickywilly stem density (per m²)||4.6||0.1||1.2||0.8||8.4||0.2||0.7||2.7||8.4||1.4||2.0||9.6|
Shrublands/grasslands: In shrubland and grassland fires, stickywilly was commonly present in the 1st postfire community. Following a July wildfire in the chaparral riparian zone of Ventura County, California, stickywilly was present 1, 2, and 3 years following fire . In west-central Utah, a fire burned big sagebrush and Colorado pinyon-Utah juniper (Pinus edulis-Juniperus osteosperma) ecosystems. Stickywilly occurred on 2 plots in the 1st postfire season but was not encountered in the 2nd or 3rd postfire years. The frequency of stickywilly on nearby unburned sites was 0 for all 3 years of postfire sampling . A late July fire in southern California's foothill chaparral vegetation produced surface temperatures of 670 °F (354 °C) and soil temperatures of 156 °F (69 °C) 2 inches (5 cm) below the soil surface. In the preburn community, stickywilly occupied 11 m²; in the 1st year postfire stickywilly occupied 32 m². Researchers indicate that annual forbs were replaced by increasingly dense grasses in the 2nd, 3rd, and 4th postfire years .
An "intense wildfire" burned Gambel oak and big sagebrush/bluebunch wheatgrass communities in the Wasatch Mountains of Utah in August of 1990. Coverage and frequency of stickywilly were greater on burned sites compared to unburned areas. The coverage and frequency (percent of quadrats in which species occurred) of stickywilly on burned and unburned plots is given below :
|Community type||Gambel oak||big sagebrush/bluebunch wheatgrass|
In northeastern Oregon, fires burned in 2 grazing exclosures (1 excluding livestock and game animals, 1 excluding just livestock) within a common snowberry-rose (Rosa spp.) community. The fire was moderately severe: it consumed the litter and woody debris, blackened shrub stems, and charred and partially burned tree trunks. Stickywilly coverage in the 5th postfire year surpassed prefire coverages in both exclosures. Prefire and postfire percent coverage for stickywilly is provided below :
moderate burn/no game or livestock postfire disturbance (n=1)
moderate burn/no livestock postfire disturbance (n=1)
|Time since fire||prefire||1 year||5 yrs||prefire||1 year||5 yrs|
While stickywilly is common in the 1st postfire year in shrub or grassland communities, some studies did not detect stickywilly the 1st season following fire. Following a November, 1994 fire in southern California's chaparral vegetation, stickywilly was not present the 1st postfire growing season. Stickywilly did occur in the 2nd, 3rd, and 4th postfire years . In a rough fescue-dominated grassland near Missoula, Montana, a late June fire burned in 1977. The fire, pushed by gusty winds, consumed virtually all above ground vegetation. The following fall (August and September) received above normal precipitation. Researchers compared burned and nearby unburned sites in the fall, spring, and summer immediately following the fire. Stickywilly was not present on burned sites by the next summer .
The following study presents more long-term fire effects information by comparing burned and unburned Gambel oak communities in central and northern Utah. On unburned sites, the average frequency of stickywilly was 36.8; on burned sites, stickywilly frequency was 33.1. A majority of the burned sites experienced fires 8 years prior, while others burned less than 30 years before initiating the study. Researchers provided no data regarding fire severity or season .
Repeated fires: Stickywilly's probability of recovery from fires seems to decrease as fire frequency increases. In a mixed mesophytic forest of northern Kentucky, sites burned repeatedly. For 2 and 3 consecutive fall seasons, prescription fires with flame heights of up to 5.9 inches (15 cm) burned. The importance of stickywilly was significantly (p<0.05) greater on unburned sites than on sites repeatedly burned . Spring fires (late March-early April) burned annually, biennially, and at 4-, 10-, and 20-year intervals in tallgrass prairie wetlands of northeastern Kansas. The relative importance of stickywilly decreased with increased fire frequency. The relative importance values (%) are provided below. Data are means and 1 standard deviation .
|Fire frequency||10 and 20||2 and 4||annual fires|
|Relative importance value||19.7±3.2||3.5±3.1||0|
Fall and spring prescribed burning in a basin big sagebrush community in east-central Oregon had no significant effect on stickywilly frequency in postfire year 1 or 2 . See the Research Project Summary of this work for more information on fire effects on stickywilly and 60 additional forb, grass, and woody plant species.
These fire studies also provide information on postfire responses of plant species in communities that include stickywilly:
Other mammals: Direct evidence of small mammal use of stickywilly is lacking. In California's Central Valley, 44.5 ringtails/mi2 are estimated to occur in the in riparian areas dominated by Fremont cottonwoods, willows, box elder, black walnut, Douglas' sagewort, California manroot, and stickywilly . Woodrats may feed on stickywilly seeds. Researchers recovered stickywilly seed from 2065- to 2800-year-old woodrat middens in northeastern California and southeastern Oregon . In Picacho Peak, Arizona, 9,400- to 13,100-year-old woodrat middens contained both seeds and leaves .
Birds: Wild turkeys, ring-necked pheasants, Canada geese, and prairie-chickens eat stickywilly seeds [56,143]. However, the stiff, hooked hairs coating the seeds may discourage predation by small birds .
Insects: Several caterpillars including the drab brown wave, common tan wave, and large lace border feed on stickywilly . Likely, many other generalist insects utilize stickywilly.
Palatability/nutritional value: Relatively little information is available on the palatability or nutritional value of stickywilly. On 15-year-old-burn sites in ponderosa pine communities of California's Teaford Forest in the Sierra Nevada, stickywilly contained 1.4% nitrogen .
Cover value: No information is available on this topic.VALUE FOR REHABILITATION OF DISTURBED SITES:
The chemical and mechanical control of stickywilly in cultivated crops is discussed in several studies [21,51,62,91].In natural settings, the presence of stickywilly may give an indication of natural regeneration following disturbances. In southwestern Oregon, stickywilly had an indicator value of 11, suggesting low to moderately low natural regeneration difficulty following clearcutting in mixed conifer and mixed evergreen forests .
1. Allman, Verl Phillips. 1953. A preliminary study of the vegetation in an exclosure in the chaparral of the Wasatch Mountains, Utah. Utah Academy Proceedings. 30: 63-78. 
2. Antos, Joseph A.; McCune, Bruce; Bara, Cliff. 1983. The effect of fire on an ungrazed western Montana grassland. The American Midland Naturalist. 110(2): 354-364. 
3. Arno, Stephen F. 1980. Forest fire history in the Northern Rockies. Journal of Forestry. 78(8): 460-465. 
4. Arno, Stephen F. 2000. Fire in western forest ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 97-120. 
5. Arno, Stephen F.; Fischer, William C. 1995. Larix occidentalis--fire ecology and fire management. In: Schmidt, Wyman C.; McDonald, Kathy J., compilers. Ecology and management of Larix forests: a look ahead: Proceedings of an international symposium; 1992 October 5-9; Whitefish, MT. Gen. Tech. Rep. GTR-INT-319. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 130-135. 
6. Arno, Stephen F.; Gruell, George E. 1983. Fire history at the forest-grassland ecotone in southwestern Montana. Journal of Range Management. 36(3): 332-336. 
7. Arno, Stephen F.; Scott, Joe H.; Hartwell, Michael G. 1995. Age-class structure of old growth ponderosa pine/Douglas-fir stands and its relationship to fire history. Res. Pap. INT-RP-481. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 25 p. 
8. Atzet, Thomas; White, Diane E.; McCrimmon, Lisa A.; Martinez, Patricia A.; Fong, Paula Reid; Randall, Vince D., tech. coords. 1996. Field guide to the forested plant associations of southwestern Oregon. Technical Paper R6-NR-ECOL-TP-17-96. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. Available online: http://www.fs.fed.us/r6/siskiyou/guide.htm [2004, October 7]. 
9. Auclair, Allan N.; Bouchard, Andre; Pajaczkowski, Josephine. 1973. Plant composition and species relations on the Huntingdon Marsh, Quebec. Canadian Journal of Botany. 51: 1231-1247. 
10. Baisan, Christopher H.; Swetnam, Thomas W. 1990. Fire history on a desert mountain range: Rincon Mountain Wilderness, Arizona, U.S.A. Canadian Journal of Forest Research. 20: 1559-1569. 
11. Bare, Janet E. 1979. Wildflowers and weeds of Kansas. Lawrence, KS: The Regents Press of Kansas. 509 p. 
12. Barrett, Stephen W. 1993. Fire regimes on the Clearwater and Nez Perce National Forests north-central Idaho. Final Report: Order No. 43-0276-3-0112. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory. 21 p. Unpublished report on file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. 
13. Barrett, Stephen W.; Arno, Stephen F.; Key, Carl H. 1991. Fire regimes of western larch - lodgepole pine forests in Glacier National Park, Montana. Canadian Journal of Forest Research. 21: 1711-1720. 
14. Belluomini, Linda; Trapp, Gene R. 1984. Ringtail distribution and abundance in the Central Valley of California. In: Warner, Richard E.; Hendrix, Kathleen M., eds. California riparian systems: Ecology, conservation, and productive management. Berkeley, CA: University of California Press: 906-914. 
15. Benvenuti, Stefano; Macchia, Mario; Miele, Sergio. 2001. Quantitative analysis of emergence of seedlings from buried weed seeds with increasing soil depth. Weed Science. 49(4): 528-535. 
16. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. 
17. Biswell, Harold H. 1973. Fire ecology in ponderosa pine-grassland. In: Komarek, Edwin V., Sr., technical coordinator. Proceedings, annual Tall Timbers fire ecology conference; 1972 June 8-9; Lubbock, TX. Number 12. Tallahassee, FL: Tall Timbers Research Station: 69-96. 
18. Bjorndalen, Jorn Erik. 1978. The chaparral vegetation of Santa Cruz Island, California. Norwegian Journal of Botany. 25: 255-269. 
19. Bliss, D.; Smith, H. 1985. Penetration of light into soil and its role in the control of seed germination. Plant, Cell and Environment. 8: 475-483. 
20. Burkhardt, Wayne J.; Tisdale, E. W. 1976. Causes of juniper invasion in southwestern Idaho. Ecology. 57: 472-484. 
21. Burrill, L. C. 1992. WEEDS--Catchweed bedstraw (Galium aparine L.). PNW 388. Corvallis, OR: Pacific Northwest Extension Service. 2 p. 
22. Carter, Christy Tucker; Ungar, Irwin A. 2002. Aboveground vegetation, seed bank and soil analysis of a 31-year-old forest restoration on coal mine spoil in southeastern Ohio. The American Midland Naturalist. 147(1): 44-59. 
23. Chappell, Christopher B.; Giglio, David F. 1999. Pacific madrone forests of the Puget Trough, Washington. In: Adams, A. B.; Hamilton, Clement W., eds. The decline of the Pacific madrone (Arbutus menziesii Pursh): Current theory and research directions: Proceedings of the symposium; 1995 April 28; Seattle, WA. Seattle, WA: Save Magnolia's Madrones, Center for Urban Horticulture, Ecosystems Database Development and Research: 2-11. 
24. Cooper, Charles F. 1961. Pattern in ponderosa pine forests. Ecology. 42(3): 493-499. 
25. Cronquist, Arthur; Holmgren, Arthur H.; Holmgren, Noel H.; [and others]. 1984. Intermountain flora: Vascular plants of the Intermountain West, U.S.A. Vol. 4. Subclass Asteridae, (except Asteraceae). New York: The New York Botanical Garden. 573 p. 
26. Davis, Frank W.; Keller, Edward A.; Parikh, Anuja; Florsheim, Joan. 1989. Recovery of the chaparral riparian zone after wildfire. In: Protection, management, and restoration for the 1990's: Proceedings of the California riparian systems conference; 1988 September 22-24; Davis, CA. Gen. Tech. Rep. PSW-110. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station: 194-203. 
27. Davis, Kathleen M. 1980. Fire history of a western larch/Douglas-fir forest type in northwestern Montana. In: Stokes, Marvin A.; Dieterich, John H., technical coordinators. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 69-74. 
28. DeFelice, Michael S. 2002. Catchweed bedstraw or cleavers, Galium aparine L.--a very "sticky" subject. Weed Technology. 16: 467-472. 
29. DeMars, Brent G.; Runkle, James R. 1992. Groundlayer vegetation ordination and site-factor analysis of the Wright State University Woods (Greene County, Ohio). Ohio Journal of Science. 92(4): 98-106. 
30. Diggs, George M., Jr.; Lipscomb, Barney L.; O'Kennon, Robert J. 1999. Illustrated flora of north-central Texas. Sida Botanical Miscellany No. 16. Fort Worth, TX: Botanical Research Institute of Texas. 1626 p. 
31. Duchesne, Luc C.; Hawkes, Brad C. 2000. Fire in northern ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 35-51. 
32. Duke, James A. 1992. Handbook of edible weeds. Boca Raton, FL: CRC Press. 246 p. 
33. Duncan, Wilbur H.; Duncan, Marion B. 1987. The Smithsonian guide to seaside plants of the Gulf and Atlantic coasts from Louisiana to Massachusetts, exclusive of lower peninsular Florida. Washington, DC: Smithsonian Institution Press. 409 p. 
34. Edgin, Bob; Ebinger, John E. 2000. Vegetation of a successional prairie at Prairie Ridge State Natural Area, Jasper County, Illinois. Castanea. 65(2): 139-146. 
35. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. 
36. Fay, Peter; Stougaard, R. N.; Keener, T. K. 1992. Weed survey of peppermint fields in the Flathead Valley, Montana. In: Lym, Rodney G., ed. Proceedings, Western Society of Weed Science; 1992 March 10-12; Salt Lake City, UT. [Place of publication unknown]: Western Society of Weed Science. 45: 47-52. 
37. Finney, Mark A.; Martin, Robert E. 1989. Fire history in a Sequoia sempervirens forest at Salt Point State Park, California. Canadian Journal of Forest Research. 19: 1451-1457. 
38. Flora of North America Association. 2004. Flora of North America: The flora. [Online]. Flora of North America Association (Producer). Available: http://www.fna.org/FNA. 
39. Gant, Robert E.; Clebsch, E. C. 1975. The allelopathic influences of Sassafras albidum in old-field succession in Tennessee. Ecology. 56: 604-615. 
40. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; Lewis, Mont E.; Smith, Dixie R. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. 
41. Gleason, Henry A.; Cronquist, Arthur. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. 2nd ed. New York: New York Botanical Garden. 910 p. 
42. Gould, Andrew M. A.; Gorchov, David L. 2000. Effects of the exotic invasive shrub Lonicera maackii on the survival and fecundity of three species of native annuals. The American Midland Naturalist. 144(1): 36-50. 
43. Graham, Joseph N.; Murray, Edward W.; Minore, Don. 1982. Environment, vegetation, and regeneration after timber harvest in the Hungry-Pickett area of southwest Oregon. Res. Note PNW-400. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 17 p. 
44. Great Plains Flora Association. 1986. Flora of the Great Plains. Lawrence, KS: University Press of Kansas. 1392 p. 
45. Greenlee, Jason M.; Langenheim, Jean H. 1990. Historic fire regimes and their relation to vegetation patterns in the Monterey Bay area of California. The American Midland Naturalist. 124(2): 239-253. 
46. Greller, Andrew M.; Locke, David C.; Kilanowski, Victoria; Lotowycz, G. Elizabeth. 1990. Changes in vegetation composition and soil acidity between 1922 and 1985 at a site on the north shore of Long Island, New York. Bulletin of the Torrey Botanical Club. 117(4): 450-458. 
47. Gruell, G. E.; Loope, L. L. 1974. Relationships among aspen, fire, and ungulate browsing in Jackson Hole, Wyoming. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 33 p. In cooperation with: U.S. Department of the Interior, National Park Service, Rocky Mountain Region. 
48. Gucker, Coery. 2004. Canyon grassland vegetation following the Maloney Creek wildfire. Moscow, ID: University of Idaho. 80 p. Thesis. 
49. Guo, Qinfeng. 2001. Early post-fire succession in California chaparral: changes in diversity, density, cover and biomass. Ecological Research. 16: 471-485. 
50. Guyette, Richard; McGinnes, E. A., Jr. 1982. Fire history of an Ozark glade in Missouri. Transactions, Missouri Academy of Science. 16: 85-93. 
51. Hann, Wendel J. 1986. Evaluation of site preparation and conifer release treatments in north Idaho shrubfields. In: Baumgartner, David M.; Boyd, Raymond J.; Breuer, David W.; Miller, Daniel L., compilers/eds. Weed control for forest productivity in the Interior West: Symposium proceedings; 1985 February 5-7; Spokane, WA. Pullman, WA: Washington State University, Cooperative Extension: 115-119. 
52. Hansen, Paul L.; Hoffman, George R.; Steinauer, Gerry A. 1984. Upland forest and woodland habitat types of the Missouri Plateau, Great Plains Province. In: Noble, Daniel L.; Winokur, Robert P., eds. Wooded draws: characteristics and values for the Northern Great Plains: Symposium proceedings; 1984 June 12-13; Rapid City, SD. Great Plains Agricultural Council Publ. No. 111. Rapid City, SD: South Dakota School of Mines and Technology, Biology Department: 15-26. 
53. Harrington, H. D. 1964. Manual of the plants of Colorado. 2d ed. Chicago: The Swallow Press, Inc. 666 p. 
54. Heinselman, M. L. 1970. Landscape evolution, peatland types and the environment in the Lake Agassiz Peatlands Natural Area, Minnesota. Ecological Monographs. 40(2): 235-261. 
55. Heyerdahl, Emily K.; Berry, Dawn; Agee, James K. 1994. Fire history database of the western United States. Final report. Interagency agreement: U.S. Environmental Protection Agency DW12934530; U.S. Department of Agriculture, Forest Service PNW-93-0300; University of Washington 61-2239. Seattle, WA: U.S. Department of Agriculture, Pacific Northwest Research Station; University of Washington, College of Forest Resources. 28 p. [+ Appendices]. Unpublished report on file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. 
56. Hilty, John. 2005. Cleavers--Galium aparine, [Online]. In: Illinois wildflowers--weedy wildflowers. John Hilty (Producer). Available: http://www.illinoiswildflowers.info/weeds/weed_index.htm [2005, March 30]. 
57. Hitchcock, C. Leo; Cronquist, Arthur. 1973. Flora of the Pacific Northwest. Seattle, WA: University of Washington Press. 730 p. 
58. Hitchcock, C. Leo; Cronquist, Arthur; Ownbey, Marion. 1959. Vascular plants of the Pacific Northwest. Part 4: Ericaceae through Campanulaceae. Seattle, WA: University of Washington Press. 510 p. 
59. Holiday, Susan. 2000. A floristic study of Tsegi Canyon, Arizona. Madrono. 47(1): 29-42. 
60. Holland, Marjorie M.; Burk, C. John. 1990. The marsh vegetation of three Connecticut River oxbows: a ten-year comparison. Rhodora. 92(871): 166-204. 
61. Holland, V. L. 1980. Effect of blue oak on rangeland forage production in central California. In: Plumb, Timothy R., technical coordinator. Proceedings of the symposium on the ecology, management, and utilization of California oaks; 1979 June 26-28; Claremont, CA. Gen. Tech. Rep. PSW-44. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station: 314-318. 
62. Holm, LeRoy G.; Plocknett, Donald L.; Pancho, Juan V.; Herberger, James P. 1977. The world's worst weeds: distribution and biology. Honolulu, HI: University Press of Hawaii. 609 p. 
63. Holmes, Kathryn L.; Semko-Duncan, Marie; Goebel, P. Charles. 2004. Temporal changes in spring ground-flora communities across riparian areas in a north-central Ohio old-growth forest. In: Yaussy, Daniel; Hix, David M.; Goebel, P. Charles; Long, Robert P., eds. Proceedings, 14th central hardwood forest conference; 2004 March 16-19; Wooster, OH. Gen. Tech. Rep. NE-316. Newton Square, PA: U.S. Department of Agriculture, Forest Service, Northeastern Research Station: 335-343. [CD]. 
64. Huff, Mark Hamilton. 1984. Post-fire succession in the Olympic Mountains, Washington: forest vegetation, fuels, and avifauna. Seattle, WA: University of Washington. 235 p. Dissertation. 
65. Hulten, Eric. 1968. Flora of Alaska and neighboring territories. Stanford, CA: Stanford University Press. 1008 p. 
66. Johnson, Charles Grier, Jr. 1998. Vegetation response after wildfires in national forests of northeastern Oregon. R6-NR-ECOL-TP-06-98. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 128 p. (+ appendices). 
67. Johnson, Stephen R.; Knapp, Alan K. 1995. The influence of fire on Spartina pectinata wetland communities in a northeastern Kansas tallgrass prairie. Canadian Journal of Botany. 73: 84-90. 
68. Johnston, Robert S.; Doty, Robert D. 1972. Description and hydrologic analysis of two small watersheds in Utah's Wasatch Mountains. Res. Pap. INT-127. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 53 p. 
69. Jones, Stanley D.; Wipff, Joseph K.; Montgomery, Paul M. 1997. Vascular plants of Texas. Austin, TX: University of Texas Press. 404 p. 
70. Kartesz, John T.; Meacham, Christopher A. 1999. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. Available: North Carolina Botanical Garden. In cooperation with the Nature Conservancy, Natural Resources Conservation Service, and U.S. Fish and Wildlife Service [2001, January 16]. 
71. Kartesz, John Thomas. 1988. A flora of Nevada. Reno, NV: University of Nevada. 1729 p. [In 3 volumes]. Dissertation. 
72. Kentucky Exotic Pest Plant Council. 2001. Invasive exotic plant list, [Online]. Southeast Exotic Pest Plant Council (Producer). Available: http://www.se-eppc.org/states/KY/KYlists.html [2005, April 13]. 
73. Kindscher, Kelly; Holah, Jenny. 1998. An old-growth definition for western hardwood galley forests. Gen. Tech. Rep. SRS-22. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 12 p. 
74. Klinka, Karel; Qian, Hong; Pojar, Jim; Meidinger, Del V. 1996. Classification of natural forest communities of coastal British Columbia, Canada. Vegetatio. 125: 149-168. 
75. Kramer, Neal B.; Johnson, Frederic D. 1987. Mature forest seed banks of three habitat types in central Idaho. Canadian Journal of Botany. 65: 1961-1966. 
76. Kron, Kathleen A. 1989. The vegetation of Indian Bowl wet prairie and its adjacent plant communities. I. Description of the vegetation. Michigan Botanist. 28(4): 179-200. 
77. Kucera, Clair L. 1952. An ecological study of a hardwood forest area in central Iowa. Ecological Monographs. 22(4): 283-299. 
78. Kucera, Clair L. 1981. Grasslands and fire. In: Mooney, H. A.; Bonnicksen, T. M.; Christensen, N. L.; [and others], technical coordinators. Fire regimes and ecosystem properties: Proceedings of the conference; 1978 December 11-15; Honolulu, HI. Gen. Tech. Rep. WO-26. Washington, DC: U.S. Department of Agriculture, Forest Service: 90-111. 
79. Kuchler, A. W. 1964. United States [Potential natural vegetation of the conterminous United States]. Special Publication No. 36. New York: American Geographical Society. 1:3,168,000; colored. 
80. Kunzler, L. M.; Harper, K. T.; Kunzler, D. B. 1981. Compositional similarity within the oakbrush type in central and northern Utah. The Great Basin Naturalist. 41(1): 147-153. 
81. Lackschewitz, Klaus. 1991. Vascular plants of west-central Montana--identification guidebook. Gen. Tech. Rep. INT-227. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 648 p. 
82. Laughlin, Daniel C. 2003. Lack of native propagules in a Pennsylvania, USA, limestone prairie seed bank: futile hopes for a role in ecological restoration. Natural Areas Journal. 23(2): 158-164. 
83. Laven, R. D.; Omi, P. N.; Wyant, J. G.; Pinkerton, A. S. 1980. Interpretation of fire scar data from a ponderosa pine ecosystem in the central Rocky Mountains, Colorado. In: Stokes, Marvin A.; Dieterich, John H., technical coordinators. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 46-49. 
84. Lawrence, George E. 1966. Ecology of vertebrate animals in relation to chaparral fire in the Sierra Nevada foothills. Ecology. 47(2): 278-291. 
85. Lenihan, James M. 1990. Forest associations of Little Lost Man Creek, Humboldt County, California: reference-level in the hierarchical structure of old-growth coastal redwood vegetation. Madrono. 37(2): 69-87. 
86. Lesica, Peter. 2001. Recruitment of Fraxinus pennsylvanica (Oleaceae) in eastern Montana woodlands. Madrono. 48(4): 286-292. 
87. Luken, J. O.; Fonda, R. W. 1983. Nitrogen accumulation in a chronosequence of red alder communities along the Hoh River, Olympic National Park, Washington. Canadian Journal of Forest Research. 13(6): 1228-1237. 
88. Luken, James O.; Shea, Margaret. 2000. Repeated prescribed burning at Dinsmore Woods State Nature Preserve (Kentucky, USA): responses of the understory community. Natural Areas Journal. 20(2): 150-158. 
89. MacDougall, Andrew. 2002. Invasive perennial grasses in Quercus garryana meadows of southwestern British Columbia: prospects for restoration. In: Standiford, Richard B.; McCreary, Douglas; Purcell, Kathryn L., technical coordinators. Proceedings of the 5th symposium on oak woodlands: oaks in California's changing landscape; 2001 October 22-25; San Diego, CA. Gen. Tech. Rep. PSW-GTR-184. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 159-168. 
90. Malik, N.; Vanden Born, W. H. 1988. The biology of Canadian weeds. 86. Galium aparine L. and Galium spurium L. Canadian Journal of Plant Science. 68: 481-499. 
91. Malik, Najib; Bowes, Garry G.; Waddington, John. 1993. Residual herbicides for weed control in established alfalfa (Medicago sativa) grown for seed. Weed Technology. 7(2): 483-490. 
92. Malik, Najib; Vanden Born, William H. 1984. False cleavers thrives on the prairies. Weeds Today. 15(4): 12-14. 
93. Martin, Jon Randall. 1989. Vegetation and environment in old growth forests of northern southeast Alaska. Tempe, AZ: Arizona State University. 221 p. Thesis. 
94. Martin, William C.; Hutchins, Charles R. 1981. A flora of New Mexico. Volume 2. Germany: J. Cramer. 2589 p. 
95. Matlack, Glenn R. 1994. Plant species in a mixed-history forest landscape in eastern North America. Ecology. 75(5): 1491-1502. 
96. McBride, Joe R. 1974. Plant succession in the Berkeley Hills, California. Madrono. 22(7): 317-380. 
97. McDonald, Philip M. 1999. Diversity, density, and development of early vegetation in a small clear-cut environment. Res. Pap. PSW-RP-239. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 22 p. 
98. Mehringer, Peter J., Jr.; Wigand, Peter E. 1987. Western juniper in the Holocene. In: Everett, Richard L., compiler. Proceedings--pinyon-juniper conference; 1986 January 13-16; Reno, NV. Gen. Tech. Rep. INT-215. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 108-119. 
99. Meinecke, E. P. 1929. Quaking aspen: A study in applied forest pathology. Tech. Bull. No. 155. Washington, DC: U.S. Department of Agriculture. 34 p. 
100. Miller, Richard F.; Rose, Jeffery A. 1995. Historic expansion of Juniperus occidentalis (western juniper) in southeastern Oregon. The Great Basin Naturalist. 55(1): 37-45. 
101. Mitchell, Laura R.; Malecki, Richard A. 2003. Use of prescribed fire for management of old fields in the Northeast. In: Galley, Krista E. M.; Klinger, Robert C.; Sugihara, Neil G., eds. Proceedings of fire conference 2000: the first national congress on fire ecology, prevention, and management; 2000 November 27-December 1; San Diego, CA. Miscellaneous Publication No. 13. Tallahassee, FL: Tall Timbers Research Station: 60-71. 
102. Moore, Michael R.; Vankat, John L. 1986. Responses of the herb layer to the gap dynamics of a mature beech-maple forest. The American Midland Naturalist. 115(2): 336-347. 
103. Moore, R. J. 1975. The Galium aparine complex in Canada. Canadian Journal of Botany. 53: 877-893. 
104. Morrison, Peter H.; Swanson, Frederick J. 1990. Fire history and pattern in a Cascade Range landscape. Gen. Tech. Rep. PNW-GTR-254. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 77 p. 
105. Munz, Philip A. 1974. A flora of southern California. Berkeley, CA: University of California Press. 1086 p. 
106. Myers, Ronald L. 2000. Fire in tropical and subtropical ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 161-173. 
107. Nixon, Elray S. 1975. Successional stages in a hardwood bottomland forest near Dallas, Texas. The Southwestern Naturalist. 20: 323-335. 
108. Oosting, Henry J. 1942. An ecological analysis of the plant communities of the Piedmont, North Carolina. The American Midland Naturalist. 28: 1-126. 
109. Ott, Jeffrey E.; McArthur, E. Durant; Sanderson, Stewart C. 2001. Plant community dynamics of burned and unburned sagebrush and pinyon-juniper vegetation in west-central Utah. In: McArthur, E. Durant; Fairbanks, Daniel J., compilers. Shrubland ecosystem genetics and biodiversity: proceedings; 2000 June 13-15; Provo, UT. Proc. RMRS-P-21. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 177-191. 
110. Pabst, Robert J.; Spies, Thomas A. 2001. Ten years of vegetation succession on a debris-flow deposit in Oregon. Journal of the American Water Resources Association. 37(6): 1693-1708. 
111. Paysen, Timothy E.; Ansley, R. James; Brown, James K.; [and others]. 2000. Fire in western shrubland, woodland, and grassland ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-volume 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 121-159. 
112. Peters, Erin F.; Bunting, Stephen C. 1994. Fire conditions pre- and postoccurrence of annual grasses on the Snake River Plain. In: Monsen, Stephen B.; Kitchen, Stanley G., compilers. Proceedings--ecology and management of annual rangelands; 1992 May 18-22; Boise, ID. Gen. Tech. Rep. INT-GTR-313. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 31-36. 
113. Pojar, Jim; MacKinnon, Andy, eds. 1994. Plants of the Pacific Northwest Coast: Washington, Oregon, British Columbia and Alaska. Redmond, WA: Lone Pine Publishing. 526 p. 
114. Poreda, Stephen F.; Wullstein, Leroy H. 1994. Vegetation recovery following fire in an oakbrush vegetation mosaic. The Great Basin Naturalist. 54: 380-383. 
115. Pratt, David W.; Black, R. Alan; Zamora, B. A. 1984. Buried viable seed in a ponderosa pine community. Canadian Journal of Botany. 62: 44-52. 
116. Pyle, Laura L. 1995. Effects of disturbance on herbaceous exotic plant species on the floodplain of the Potomac River. The American Midland Naturalist. 134(2): 244-253. 
117. Quinnild, Clayton L.; Cosby, Hugh E. 1958. Relicts of climax vegetation on two mesas in western North Dakota. Ecology. 39(1): 29-32. 
118. Radford, Albert E.; Ahles, Harry E.; Bell, C. Ritchie. 1968. Manual of the vascular flora of the Carolinas. Chapel Hill, NC: The University of North Carolina Press. 1183 p. 
119. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. 
120. Riegel, Gregg M.; Smith, Bradley G.; Franklin, Jerry F. 1992. Foothill oak woodlands of the interior valleys of southwestern Oregon. Northwest Science. 66(2): 66-76. 
121. Ripple, William J. 1994. Historic spatial patterns of old forests in western Oregon. Journal of Forestry. 92(11): 45-49. 
122. Roberts, Catherine Anne. 1975. Initial plant succession after brown and burn site preparation on an alder-dominated brushfield in the Oregon Coast Range. Corvallis, OR: Oregon State University. 90 p. Thesis. 
123. Roper, Laren Alden. 1970. Some aspects of the synecology of Cornus nuttallii in northern Idaho. Moscow, ID: University of Idaho. 81 p. Thesis. 
124. Royer, France; Dickinson, Richard. 1999. Weeds of the northern U.S. and Canada: A guide for identification. Edmonton, AB: The University of Alberta Press; Renton, WA: Lone Pine Publishing. 434 p. 
125. Salstrom, Debra. 1989. Plant community dynamics associated with Quercus garryana on Pt. Disney, Waldron Island, Washington. Bellingham, WA: Western Washington University. 36 p. Thesis. 
126. Sapsis, David B. 1990. Ecological effects of spring and fall prescribed burning on basin big sagebrush/Idaho fescue--bluebunch wheatgrass communities. Corvallis, OR: Oregon State University. 105 p. Thesis. 
127. Schwartz, Mark W.; Heim, James R. 1996. Effects of a prescribed fire on degraded forest vegetation. Natural Areas Journal. 16(3): 184-191. 
128. Seklecki, Mariette T.; Grissino-Mayer, Henri D.; Swetnam, Thomas W. 1996. Fire history and the possible role of Apache-set fires in the Chiricahua Mountains of southeastern Arizona. In: Ffolliott, Peter F.; DeBano, Leonard F.; Baker, Malchus, B., Jr.; [and others], tech. coords. Effects of fire on Madrean Province ecosystems: a symposium proceedings; 1996 March 11-15; Tucson, AZ. Gen. Tech. Rep. RM-GTR-289. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 238-246. 
129. Seymour, Frank Conkling. 1982. The flora of New England. 2d ed. Phytologia Memoirs 5. Plainfield, NJ: Harold N. Moldenke and Alma L. Moldenke. 611 p. 
130. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. 
131. Small, Christine J.; McCarthy, Brian C. 2002. Effects of simulated post harvest light availability and soil compaction on deciduous forest herbs. Canadian Journal of Forest Research. 32(10): 1753-1762. 
132. Spies, Thomas A. 1991. Plant species diversity and occurrence in young, mature, and old-growth Douglas-fir stands in western Oregon and Washington. In: Ruggiero, Leonard F.; Aubry, Keith B.; Carey, Andrew B.; Huff, Mark H., technical coordinators. Wildlife and vegetation of unmanaged Douglas-fir forests. Gen. Tech. Rep. PNW-GTR-285. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 111-121. 
133. Staniforth, Richard J.; Scott, Peter A. 1991. Dynamics of weed populations in a northern subarctic community. Canadian Journal of Botany. 69: 814-821. 
134. Stevens, Lawrence E.; Ayers, Tina. 2002. The biodiversity and distribution of exotic vascular plants and animals in the Grand Canyon region. In: Tellman, Barbara, ed. Invasive exotic species in the Sonoran region. Arizona-Sonora Desert Museum Studies in Natural History. Tucson, AZ: The University of Arizona Press; The Arizona-Sonora Desert Museum: 241-265. 
135. Stevens, O. A. 1956. Flowering dates of weeds in North Dakota. North Dakota Agricultural Experiment Station Bimonthly Bulletin. 18(6): 209-213. 
136. Stevens, O. A. 1957. Weights of seeds and numbers per plant. Weeds. 5: 46-55. 
137. Stickney, Peter F. 1989. FEIS postfire regeneration workshop--April 12: Seral origin of species comprising secondary plant succession in Northern Rocky Mountain forests. 10 p. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 
138. Stickney, Peter F.; Campbell, Robert B., Jr. 2000. Data base for early postfire succession in northern Rocky Mountain forests. Gen. Tech. Rep. RMRS-GTR-61-CD, [CD-ROM]. Fort Collins, CO: U.S. Department of Agriculture, Forest Service (Producer). Available: Rocky Mountain Research Station. 
139. Strausbaugh, P. D.; Core, Earl L. 1977. Flora of West Virginia. 2nd ed. Morgantown, WV: Seneca Books, Inc. 1079 p. 
140. Stromberg, Juliet C. 1998. Functional equivalency of saltcedar (Tamarix chinensis) and Fremont cottonwood (Populus fremontii) along a free-flowing river. Wetlands. 18(4): 675-686. 
141. Struik, Gwendolyn J.; Curtis, J. T. 1962. Herb distribution in an Acer saccharum forest. The American Midland Naturalist. 68(2): 285-296. 
142. Stuart, John D. 1987. Fire history of an old-growth forest of Sequoia sempervirens (Taxodiaceae) forest in Humboldt Redwoods State Park, California. Madrono. 34(2): 128-141. 
143. Stubbendieck, James; Coffin, Mitchell J.; Landholt, L. M. 2003. Weeds of the Great Plains. 3rd ed. Lincoln, NE: Nebraska Department of Agriculture, Bureau of Plant Industry. 605 p. In cooperation with: University of Nebraska - Lincoln. 
144. Sugihara, Neil G.; Reed, Lois J.; Lenihan, James M. 1987. Vegetation of the Bald Hills oak woodlands, Redwood National Park, California. Madrono. 34(3): 193-208. 
145. Sullivan, Thomas P. 1979. Virgin Douglas-fir forest on Saturna Island, British Columbia. Canadian Field-Naturalist. 93(2): 126-131. 
146. Taft, John B. 2003. Composition and structure of an old-growth floodplain forest of the lower Kaskaskia River. In: Van Sambeek, J. W.; Dawson, J. O.; Ponder, F., Jr.; Loewenstein, E. F.; Fralish, J. S., eds. Proceedings, 13th central hardwood forest conference; 2002 April 1-3; Urbana, IL. Gen. Tech. Rep. NC-234. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Research Station: 146-158. 
147. Tande, Gerald F. 1979. Fire history and vegetation pattern of coniferous forests in Jasper National Park, Alberta. Canadian Journal of Botany. 57: 1912-1931. 
148. Thieret, John W. 1971. Quadrat study of a bottomland forest in St. Martin Parish, Louisiana. Castanea. 36: 174-181. 
149. Thomas, A. G. 1991. Floristic composition and relative abundance of weeds in annual crops of Manitoba. Canadian Journal of Plant Science. 71(3): 831-839. 
150. Thomas, A. G.; Donaghy, D. I. 1991. A survey of the occurrence of seedling weeds in spring annual crops in Manitoba. Canadian Journal of Plant Science. 71(3): 811-820. 
151. Thysell, David R.; Carey, Andrew B. 2000. Effects of forest management on understory and overstory vegetation: a retrospective study. Gen. Tech. Rep. PNW-GTR-488. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 41 p. 
152. U.S. Department of Agriculture, Agricultural Research Service. 1971. Common weeds of the United States. New York: Dover Publications, Inc. 463 p. 
153. U.S. Department of Agriculture, National Resource Conservation Service. 2005. PLANTS database (2004), [Online]. Available: http://plants.usda.gov/. 
154. University of Montana, Division of Biological Sciences. 2001. INVADERS Database System, [Online]. Available: http://invader.dbs.umt.edu/ [2001, June 27]. 
155. Van Devender, Thomas R.; Mead, Jim I.; Rea, Amadeo M. 1991. Late Quaternary plants and vertebrates from Picacho Peak, Arizona. The Southwestern Naturalist. 36(3): 302-314. 
156. Vincent, Dwain W. 1992. The sagebrush/grasslands of the upper Rio Puerco area, New Mexico. Rangelands. 14(5): 268-271. 
157. Vora, Robin S. 1990. Plant phenology in the lower Rio Grande Valley, Texas. Texas Journal of Science. 42(2): 137-142. 
158. Voss, Edward G. 1996. Michigan flora. Part III: Dicots (Pyrolaceae--Compositae). Cranbrook Institute of Science Bulletin 61/University of Michigan Herbarium. Ann Arbor, MI: The Regents of the University of Michigan. 622 p. 
159. Wade, Dale D.; Brock, Brent L.; Brose, Patrick H.; [and others]. 2000. Fire in eastern ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 53-96. 
160. Weaver, J. E.; Rowland, N. W. 1952. Effects of excessive natural mulch on development, yield, and structure of native grassland. Botanical Gazette. 114(1): 1-19. 
161. Welsh, Stanley L.; Atwood, N. Duane; Goodrich, Sherel; Higgins, Larry C., eds. 1987. A Utah flora. The Great Basin Naturalist Memoir No. 9. Provo, UT: Brigham Young University. 894 p. 
162. Whisenant, Steven G. 1990. Postfire population dynamics of Bromus japonicus. The American Midland Naturalist. 123: 301-308. 
163. White, Keith L. 1966. Old-field succession on Hastings Reservation, California. Ecology. 47(5): 865-868. 
164. Whitson, Tom D.; Burrill, Larry C.; Dewey, Steven A.; [and others]. 1999. Weeds of the West. 5th edition. Laramie, WY: University of Wyoming; The Western Society of Weed Science. In cooperation with the Western United States Land Grant Universities, Cooperative Extension Services. 630 p. 
165. Wiggins, Ira L. 1980. Flora of Baja California. Stanford, CA: Stanford University Press. 1025 p. 
166. Wilhelm, Gerould S. 1991. Implicatons of changes in floristic composition of the Morton Arboretum's East Woods. In: Burger, George V.; Ebinger, John E.; Wilhelm, Gerould S., eds. Proceedings of the oak woods management workshop; 1988 October 21-22; Peoria, IL. Charleston, IL: Eastern Illinois University: 31-54. 
167. Wofford, B. Eugene. 1989. Guide to the vascular plants of the Blue Ridge. Athens, GA: The University of Georgia Press. 384 p. 
168. Wright, Henry A. 1978. The effect of fire on vegetation in ponderosa pine forests: A state-of-the-art review. Lubbock, TX: Texas Tech University, Department of Range and Wildlife Management. 21 p. In cooperation with: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 
169. Wright, Henry A.; Bailey, Arthur W. 1982. Fire ecology: United States and southern Canada. New York: John Wiley & Sons. 501 p. 
170. Wunderlin, Richard P. 1998. Guide to the vascular plants of Florida. Gainesville, FL: University Press of Florida. 806 p. 
171. Yost, Susan E.; Antenen, Susan; Harvigsen, Gregg. 1991. The vegetation of the Wave Hill Natural Area, Bronx, New York. Torreya. 118(3): 312-325. 
172. Young, James A.; Evans, Raymond A. 1981. Demography and fire history of a western juniper stand. Journal of Range Management. 34(6): 501-505.