|Figure 1. Wavyleaf soap plant flowers. Image ©2010 Barry Breckling.|
|Figure 2. Wavyleaf soap plant distribution. Map courtesy of USDA, NRCS. 2015. The PLANTS Database. National Plant Data Team, Greensboro, NC. (2015, June 9) .|
Wavyleaf soap plant occurs in the following ecosystems, areas, and plant communities:ECOSYSTEMS :
Wavyleaf soap plant is not documented as an indicator or a dominant species in vegetation types of California and Oregon. Vegetation classifications in which wavyleaf soap plant was descrbied as an important component of the plant community follow:
knobcone pine (Pinus attenuata) communities 
purple needlegrass (Nassella pulchra) associations south and east of Monterey 
abundant in chamise chaparral 
Bald Hills oak woodlands, Redwood National Park:
Wavyleaf soap plant showed 0.78% frequency in an Oregon white oak/common snowberry (Quercus garryana/Symphoricarpos albus var. laevigatus) community and 0.83% frequency in an Oregon white oak/orchard grass (Dactylis glomerata) community on mesic, lower concave slopes. It had 0.50% frequency in a mockorange/brittle bladder-fern (Philadelphus lewisii/Cystopteris fragilis) stream channel community with a dense shrub layer. Wavyleaf soap plant had 0.75% frequency in a Sierra gooseberry/varileaf phacelia (Ribes roezlii/Phacelia heterophylla) community, a rock outcrop type with a moderately dense shrub layer. Its cover ranged from 1% to 5% cover in all of thesecommunities .
Pinnacles National Monument: Wavyleaf soap plant occurred in chamise chaparral with 16.7% mean frequency and 3% mean cover.
Ring Mountain Preserve, Marin County: Wavyleaf soap plant was common in a serpentine bunchgrass community (characterized by many boulders strewn among native perennial grasses and bulbous plant species), with 9.48% average frequency on north- and south-facing slopes and on ridgetops. It had 0.84% frequency in the nonnative annual grassland community. Wavyleaf soap plant had 3.3% cover in a coyotebrush (Baccharis pilularis) community (a steppe grassland characterized by slopes) and 6.47% frequency in a freshwater seep community (characterized by the presence of surface water, although some drainages typically dry completely by June) .Santa Ana Mountains: On a serpentine site dominated by knobcone pine, wavyleaf soap plant occupied exposed sites with 7% cover, but it was not found in surrounding chaparral .
GENERAL BOTANICAL CHARACTERISTICS:
The following description of wavyleaf soap plant provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available [27,38,44,45].
Wavyleaf soap plant is a native perennial forb. It has a basal tuft of wavy, 1-inch (2.5 cm) wide, linear leaves [13,14,15,29,30,45]. Exposure to sunlight tends to increase the wave patterns in leaf edges . The leaves are flaccid and stretch along the ground up to 18 inches (46 cm). The star-like flowers are borne on a leafless stalk that may grow to 6 feet (1.8 m) tall. The flowers open sequentially from bottom to top of the stalk. Each flower displays for just 1 day, opening in late afternoon and closing before dawn [13,14,15,29,30,45]. There may be just a few to more than 200 flowers per plant . The fruit is a capsule  with 1 or 2 seeds per locule . The bulb is large—from 3 to 6 inches (7-15 cm) long and 1 to 3 inches (3-8 cm) wide—and covered with persistent, dense fibers (see Figure 4). Its fresh weight ranges from 0.7 to 12 ounces (20-350 g) [9,13,14,44]. Bulbs of mature plants are buried 4 to 12 inches (10-30 cm) underground. Contractile roots attach to the base of the bulb; these roots pull the bulb downward, so the bulb becomes more deeply buried over the life of the plant .
|Figure 4. Wavyleaf soap plant bulb and contractile roots. Image by Jim Conrad.|
In the Ojai Ranger District of the Los Padres National Forest, total mortality rate of a wavyleaf soap plant population was 43% (13 of 30 plants) over 8 years. Causes of mortality were unknown, but annual mortality was not correlated with precipitation of the current or previous year .RAUNKIAER  LIFE FORM:
Pollination: There is only a small window of time in which individual flowers of wavyleaf soap plant can be pollinated, since each flower opens for only 1 afternoon and evening [29,59]. During the day, large bees (honeybees, carpenter bees, and 2 species of bumblebee) pollinate the flowers; rare or infrequent visits are made by yellowjackets, mining bees (Lasioglossum sisymbrii), and Allen's hummingbirds . After dark, sphingid moths visit the flowers . Removal of the shrub layer and the subsequent increase in light availability after fire may enhance pollination rates  (see Fire Ecology or Adaptations).
Breeding system: A laboratory study showed that wavyleaf soap plants are self-compatible ; however, in the field, most pollination is probably accomplished by insects [30,59].
Flower and seed production: It takes 5 to 7 years for plants to reach reproductive age . Limited data suggest that wavyleaf soap plant does not produce flowers and seeds every year. Two populations on the Los Padres National Forest showed a pattern of alternating years of mass flowering with years of little to no flowering. For individual plants, the probability of producing a flower stalk was positively associated with leaf area (P=0.2). High rates of leaf herbivory were negatively associated with flower production (P<0.0002) .
Wavyleaf soap plant flower and seed production increase after fire and other canopy-opening disturbances [8,9,22]. In California chaparral, geophytes such as wavyleaf soap plant typically show good seed production the 1st year after fire . On the Los Padres National Forest, wavyleaf soap plant had higher seed production the year after a prescribed fire than on an adjacent unburned site  (see Plant Response to Fire).
Seed dispersal: Seeds are dispersed by gravity  and usually fall beneath parent wavyleaf soap plants .
Seed banking: Wavyleaf soap plant apparently has a short-lived seed bank , but as of 2015, studies on the longevity of wavyleaf soap plant seeds in the field had not been conducted.
Germination: Wavyleaf soap plant seeds are not dormant . Viable seeds germinate readily upon wetting, incubating under moderate temperatures [3,34]. In the laboratory, seeds germinated about 7 days after imbibition .
Seedling establishment and plant growth: In California chaparral, seedling establishment for most geophytes, such as wavyleaf soap plant, is most common in postfire year 2, when light and nutrient levels remain high but interference from shrubs, herbivory, and seed predation are still low . In order to survive summer drought, seedlings must rapidly develop a large bulb and an adequate root system .
Asexual regeneration: Wavyleaf soap plant sprouts from the bulb. If disturbances such as fire or rockslide top-kill wavyleaf soap plant during its growing season, it typically sprouts soon after top-kill [3,34]. If the disturbance occurs after plants have already senesced, plants resume growth as usual the next growing season . Vegetative reproduction also occurs by bulb splitting or division, but whether bulb splitting occurs naturally in not known . Sierra Miwoks would often break bulbs apart when harvesting wavyleaf soap plant (see Other Uses), leaving some bulb and root tissue behind to regenerate .
Bulb dormancy was rare in an 8-year study on the Los Padres National Forest. Typically, individual wavyleaf soap plants sprouted every year. If they failed to sprout one year, they also failed to sprout in subsequent years and were presumed dead .SITE CHARACTERISTICS:
Wavyleaf soap plant grows from low to midelevations. The following table provides elevations where wavyleaf soap plant has been collected.
|Table 1. Elevational ranges of wavyleaf soap plant across its distribution|
|Oregon (southwestern)||below 5,000 feet (1,524 m) |
|California (across the state)||below 5,000 feet (1,524 m) [27,45,59]|
|Elk Creek Drainage (Sequoia National Park)||2,100 feet (640 m) |
|Hastings Natural History Reservation, San Lucia Range, Monterey County||860 to 3,600 feet (262-1,050 m) |
|Pinnacles National Monument||1,200 to 3,000 feet (370-910 m) |
|Donald and Sylvia McLaughlin University of California Natural Reserve||1,200 to 3,100 feet (370-950 m) |
|central Sierra Nevada||up to 6,000 feet (1,800 m) |
|Santa Ana Mountains||average 3,500 feet (1,100 m) |
Fire regimes: The plant communities in which wavyleaf soap plant occurs have a variety of fire regimes. Chaparral communities, in which wavyleaf soap plant is common, have frequent, stand-replacing fires at less than 100-year intervals . The low-elevation oak and low-elevation ponderosa pine woodlands, in which soap plant is also common, historically had mostly frequent, low-severity surface fires . Higher-elevation mixed-conifer communities had mixed-severity and occasional stand-replacement fires at longer intervals .
The following table provides fire return intervals for plant communities and ecosystems where wavyleaf soap plant is important. For further information, see the FEIS Species Review of the dominant species listed below. Find more fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes".
|Table 2. Fire regimes of plant communities in which wavyleaf soap plant occurs|
|Community or ecosystem||Dominant species||Fire return interval range (years)|
|California chaparral||Adenostoma and/or Arctostaphylos spp.||<35 to <100|
|coastal sagebrush||Artemisia californica||<35 to <100|
|California montane chaparral||Ceanothus and/or Arctostaphylos spp.||50-100 |
|California steppe||Festuca-Danthonia spp.||<35 [47,62]|
|Jeffrey pine||Pinus jeffreyi||5-30|
|Pacific ponderosa pine*||Pinus ponderosa var. ponderosa||1-47|
|California mixed conifer||Pinus ponderosa var. ponderosa-Abies concolor-P. lambertiana||10-150 |
|California mixed evergreen||Pseudotsuga menziesii var. menziesii-Lithocarpus densiflorus-Arbutus menziesii||<35|
|California oakwoods||Quercus spp.||<35 |
|coast live oak||Quercus agrifolia||2-75 |
|canyon live oak||Quercus chrysolepis||<35 to 200|
|blue oak-foothills pine||Quercus douglasii-P. sabiniana||<35|
|Oregon white oak||Quercus garryana||<35 |
|California black oak||Quercus kelloggii||5-30 |
|*Fire return interval varies widely; trends in variation are noted in the Species Review.|
IMMEDIATE FIRE EFFECT ON PLANT:
Because the leaves and flower stalk are desiccated by late summer and early fall [2,9] (see Seasonal Development), wavyleaf soap plant is little affected by fires that occur during the fire season . Fires that occur from winter to midsummer—during wavyleaf soap plant's growing season—top-kill mature plants . Fires in any season may kill seedlings with small, shallowly buried bulbs. The bulbs of mature plants are usually well protected from fire, regardless of when fire occurs [22,35,40]. Since wavyleaf soap plant has contractile roots that pull the bulb deeper underground throughout the plant's life (see General Botanical Characteristics), the bulb becomes increasingly protected from fire as the plant ages.
As of 2015, the effect of fire on the seeds was unknown. Since this species has an apparently short-lived seed bank that is replenished soon after fire, seeds present in the soil seed bank before fire may not be important for wavyleaf soap plant's postfire regeneration.
PLANT RESPONSE TO FIRE:
Wavyleaf soap plant sprouts from its deeply buried bulbs after fire, and it shows "vigorous" growth and masting in the first postfire year [5,7,9,34,35,36,43]. Population size may be larger than prefire levels for 4 or more postfire years [5,55,64]. Postfire sprouting occurs in late fall or winter, during the plant's normal growth cycle  (see Seasonal Development). The postfire release of nutrients, increased light, and removal of competing vegetation favors wavyleaf soap plant growth and flowering in early postfire environments . Reynolds  suggested that wavyleaf soap plant prefers burned or other disturbed sites and that periodic burning is required to maintain healthy populations.
|Figure 5. Wavyleaf soap plant sprouting in a mixed-conifer habitat, 15 months after the 2013 Rim Wildfire on the Stanislaus National Forest. Photo by Becky Howard.|
Many have noted that wavyleaf soap plant is abundant and widespread on burns [8,39,55,56,64]. Sampson  called it "one of the most conspicuous broad-leaved herbs" on new chaparral burns. After 2 fires in northern California (Mendocino and Shasta counties), density of wavyleaf soap plant increased for at least 5 postfire years (see Table 3). The fire in Mendocino County occurred in September. Sampson  did not provide timing of the fire in Shasta County and did not note whether these fires were prescribed or wild.
|Table 3. Wavyleaf soap plant density (plants/milacre) before and after fires in northern California |
|Mendocino County/chamise chaparral||0.6||2.7||3.5||2.1||2.1||2.0|
|Shasta County/interior live oak-blue oak||0.1||1.4||1.3||0.7||0.4||0.4|
This study suggests that wavyleaf soap plant populations peak in postfire years 2 or 3 but remain large for at least 4 or 5 postfire years. Sweeney  also noted that wavyleaf soap plant abundance increased in postfire years 2 and 3. Barbour and others  suggested that wavyleaf soap plant numbers remain constant for up to 4 years after fire.
On the Los Padres National Forest, wavyleaf soap plant showed enhanced flower and seed production after prescribed and wildfires. On the Ojai Ranger District, 640 acres (260 ha) of a chamise community was burned under prescription in October 1997. Fire severity was low to moderate. Prefire density of wavyleaf soap plant was higher on the site targeted for burning (Site 1, with 1.9 plants/m²) than on the unburned control (Site 2, with 0.5 plant/m²). Prior to the fire, neither site had burned for over 100 years. The year after the prescribed fire (1998), flower production (flowers/plant) was significantly higher on Site 1 (burned) than on Site 2 (unburned) (P=0.5). In late December 1999, a wildfire burned both sites. On Site 1 (Rx + wildfire), the percentage of flowering stalks was highest year after the prescribed fire. On Site 2 (wildfire only), it was highest after the wildfire. Flower stalk production was synchronous between the 2 sites (P=0.0008), and there was a pattern of alternating years of flowering and no flowering  (Figure 6).
|Figure 6. Percentage of wavyleaf soap plant individuals flowering after prescribed fire and wildfire on 2 study sites on Los Padres National Forest. The prescribed fire was conducted at Site 1 in 1997, and wildfire burned both sites in late 1999 .|
On Site 1, flower production increased again in 2000 (after the wildfire), but it did not exceed production of 1999 (the 2nd year after the prescribed fire). On Site 2 , flower production was highest in 2000 (Figure 7). Fruit production generally followed the trend of flower production at both sites. The authors concluded that in this study, fire stimulated flowering and seed production in wavyleaf soap plant but was not required for its reproduction. They noted that whether high postfire seed production results in high seedling establishment is not well known .
|Figure 7. Flowers per plant at each site .|
FIRE MANAGEMENT CONSIDERATIONS:
Wavyleaf soap plant is well adapted to survive fire and flourish in the open conditions characteristic of early postfire communities. Because it was a valued resource, Pomo Indians burned areas where wavyleaf soap plant grew often enough to reduce other vegetation and maintain open communities, favoring wavyleaf soap planbt growth and reproduction . In a study in the Bald Hills of Redwood National Park, wavyleaf soap plant was positively associated with Oregon white oak woodlands (P=0.04) that were burned under prescription at 3- to 5-year intervals. It had "high indicator value" for intact burned woodlands: those that still retained the open structure characteristic of the Bald Hills . This species responds favorably to prescribed and wildfires.
|Figure 8. Mule deer eating wavyleaf soap plant leaves. Image by Trevor Hebert, Jasper Ridge Biological Preserve.|
Although livestock use of wavyleaf soap plant is not well documented, it is likely consumed when available. Sampson  reported that wavyleaf soap plant is "closely cropped" by cattle, domestic sheep, and domestic goats. On the Hastings Natural History Reservation and the Santa Lucia Range in Monterey County, wavyleaf soap plant occurred only on sites without livestock .
Palatability/nutritional value: Frequent use of wavyleaf soap plant leaves and flower stalks by wildlife [16,28,36,49] suggests that its palatability is good.
Cover value: Wavyleaf soap plant is too small to provide cover for vertebrates.
VALUE FOR REHABILITATION OF DISTURBED SITES:
Wavyleaf soap plant has been used for restoration. The US Army Corps of Engineers propagated wavyleaf soap plant from seed (in a nursery) for revegetating wildlife habitat in their Los Angeles District . Seeds of wavyleaf soap plant were collected and hydroseeded on San Bruno Mountain, San Bruno State Park , although rate of establishment was not reported.
PLANTS Database  provides information on propagating wavyleaf soap plant.
Wavyleaf soap plant is planted for landscaping .
Wavyleaf soap plant was traditionally used by Indians and early settlers . Tribes using wavyleaf soap plant included but were not limited to the Miwok, Hulpumne Yokuts, and Wailakis [1,3,13,51]. Highly sought for food, utensils, and medicine, wavyleaf soap plant was one of the most versatile plants in the Miwok economy .
There were many traditional uses of wavyleaf soap plant. The starchy bulb was used as food and for making utensils . It was boiled or roasted to remove soapy taste, then eaten like a potato. The young shoots, when thoroughly roasted, are said to be as "sweet as sugar" [13,65]. Wavyleaf soap plant was used as emergency food during lean acorn years . The leaves, which are flexible and half-succulent, were used to cover bread dough while baking . The bulb in particular had multiple uses. Fibers from the bulb were used to stuff mattresses and to make brushes, ropes, and baskets [13,14,42,65]. The bulb contains saponin, a soap substitute [2,15], and the bulbs were crushed to make a lather for laundry and bathing. When the bulb and young shoots are boiled, a resinous substance is exuded that was used as a glue to attach feathers to arrow shafts [13,14]. The roasted bulb was used antiseptically as a poultice for sores. The Wailakis used it on the body for cramps and for rheumatism. A decoction of the bulb was also used as a diuretic and laxative .
|Figure 9. Brush made from the outer fibers of a wavyleaf soap plant bulb. California Indians used these brushes to sweep acorn meal from grinding rocks into baskets. Image by Cait Hutnik.|
California Indians also used wavyleaf soap plant bulbs for fishing. They crushed the bulbs, worked them into a lather, and threw them into quiet pools. The saponin in the lather stunned and immobilized fish, causing them to float to the top of the water where they were easily caught [2,13,14,42].OTHER MANAGEMENT CONSIDERATIONS:
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