Index of Species Information

SPECIES:  Lolium multiflorum


SPECIES: Lolium multiflorum
AUTHORSHIP AND CITATION : Carey, Jennifer H. 1995. Lolium multiflorum. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [].
ABBREVIATION : LOLMUL SYNONYMS : Lolium perenne subsp. multiflorum (Lam.) Husnot [70] Lolium perenne var. aristatum Willd. [20,21] SCS PLANT CODE : LOPEM2 COMMON NAMES : Italian ryegrass annual ryegrass darnel TAXONOMY : The currently accepted scientific name for Italian ryegrass is Lolium multiflorum Lam. (Poaceae) [31,33,59]. Some authors consider Italian ryegrass to be a variety or subspecies of perennial ryegrass (L. perenne) [20,21,61,64]. However, Terrell [59], who wrote the monograph for the Lolium genus in 1968, provisionally considered them separate species and listed the primary distinguishing characteristics. Recent genetic work indicates that they are distinct species, both possibly originating from a common ancestor, Wimmera ryegrass (L. rigidum) [8,41]. The divergence of Italian ryegrass from Wimmera ryegrass is hypothesized to have occurred fairly recently, perhaps 6,000 years ago [8]. Natural hybrids of Italian ryegrass and perennial ryegrass are interfertile [8,41]. Natural and artificial interspecific and intergeneric crosses are discussed [58]. LIFE FORM : Graminoid FEDERAL LEGAL STATUS : No special status OTHER STATUS : NO-ENTRY


SPECIES: Lolium multiflorum
GENERAL DISTRIBUTION : Italian ryegrass, native to Europe, has been introduced throughout the temperate regions of the world as an agricultural species. Records of its cultivation in Italy date back to the thirteenth and fourteenth centuries [59]. Italian ryegrass occurs throughout the United States, including Alaska and Hawaii, and in adjacent Canadian provinces [20,31,35]. Because of difficulties in distinguishing Italian ryegrass from perennial ryegrass, the exact northern distribution of Italian ryegrass is not well documented. ECOSYSTEMS : Italian ryegrass probably occurs in most ecosystems. STATES : AL AK AZ AR CA CO CT DE FL GA HI ID IL IN IA KS KY LA ME MD MA MI MN MS MO MT NE NV NH NJ NM NY NC ND OH OK OR PA RI SC SD TN TX UT VT VA WA WV WI WY AB BC MB NB NF NS ON PE PQ SK MEXICO BLM PHYSIOGRAPHIC REGIONS : 1 Northern Pacific Border 2 Cascade Mountains 3 Southern Pacific Border 4 Sierra Mountains 5 Columbia Plateau 6 Upper Basin and Range 7 Lower Basin and Range 8 Northern Rocky Mountains 9 Middle Rocky Mountains 10 Wyoming Basin 11 Southern Rocky Mountains 12 Colorado Plateau 13 Rocky Mountain Piedmont 14 Great Plains 15 Black Hills Uplift 16 Upper Missouri Basin and Broken Lands KUCHLER PLANT ASSOCIATIONS : NO-ENTRY SAF COVER TYPES : 243 Sierra Nevada mixed conifer 245 Pacific ponderosa pine 250 Blue oak-foothills pine 255 California coast live oak SRM (RANGELAND) COVER TYPES : 201 Blue oak woodland 202 Coast live oak woodland 206 Chamise chaparral 208 Ceanothus mixed chaparral 214 Coastal prairie 215 Valley grassland 605 Sandsage prairie 606 Wheatgrass-bluestem-needlegrass 607 Wheatgrass-needlegrass 608 Wheatgrass-grama-needlegrass 611 Blue grama-buffalograss Italian ryegrass may occur in other SRM cover types as well. HABITAT TYPES AND PLANT COMMUNITIES : Italian ryegrass occurs in grassland communities. It is a component of the California annual grasslands, a community composed of exotic grass species [6,28]. It occurs in a serpentine bunchgrass community, a freshwater seep community, and a non-native grassland community in Ring Mountain Preserve in California [16].


SPECIES: Lolium multiflorum
IMPORTANCE TO LIVESTOCK AND WILDLIFE : Italian ryegrass is an important forage crop for livestock [53]. Meadow mice and white-tailed deer graze Italian ryegrass [38,47]. PALATABILITY : Italian ryegrass is palatable to livestock [53]. NUTRITIONAL VALUE : Italian ryegrass is highly nutritious [53]. Fresh, early bloom, aerial portions of Italian ryegrass average 8.1 percent ash, 30.1 percent crude fiber, 5.8 percent protein, 55.2 nitrogen-free extract, and 0.8 percent ether extract (dry weight). Nutritional values for other Italian ryegrass growth stages and for hay are reported [68]. The influence of shading, sward density, and nitrogen fertilizer on Italian ryegrass nutritive value is reported [36]. COVER VALUE : Italian ryegrass is considered poor cover for small mammals and waterfowl in Montana [13]. Pocket gophers increase in areas seeded with Italian ryegrass, possibly because of increased cover [57]. VALUE FOR REHABILITATION OF DISTURBED SITES : Italian ryegrass is a quick, effective groundcover for erosion control and as a winter cover crop [25]. It is often used for temporary erosion control; it does not generally persist in cold ecosystems such as in Alaska, nor does it tend to spread into adjacent undisturbed areas [12]. It has a lower pH limit of 4.5. Seeding rates are described [63]. Seeding of Italian ryegrass is often followed by seeding with perennial species the following year. If seeded together, Italian ryegrass often outcompetes the perennials [25,63]. Although Italian ryegrass is one of the most commonly used grasses for revegetating burned sites, its use is controversial. Discussion of this controversy is in FIRE MANAGEMENT. OTHER USES AND VALUES : Italian ryegrass is used as turf grass in the southern United States [17]. OTHER MANAGEMENT CONSIDERATIONS : Italian ryegrass is grown for winter pasture, hay, and silage. In the United States it is cultivated primarily on the Atlantic Coast, in southern humid areas, and on the Pacific Coast west of the Cascade Range and Sierra Nevada. There are over 150 recognized cultivars of Italian and perennial ryegrasses. Planting and harvesting methods are discussed [17]. Nitrogen, phosphorus, and calcium are required for high quality Italian ryegrass production [49]. Italian ryegrass is a serious weed in cereal crops and grass seed crops [51,54]. In western Oregon, where most of the Italian ryegrass seed is produced, seed remains dormant in the cold, wet soil during winter and then volunteers in crops when fields are plowed. Diclofop has been an effective herbicide, but Italian ryegrass is gaining resistance to it [51]. Italian ryegrass cultivars have also developed a tolerance of the herbicide fenoxaprop [27].


SPECIES: Lolium multiflorum
GENERAL BOTANICAL CHARACTERISTICS : Italian ryegrass is an introduced, annual or biennial, cool-season bunchgrass. The erect, spreading, or decumbent culms grow 50 inches (127 cm) tall. Spikelets are 11- to 22-flowered; lemmas are usually awned [59]. Roots are shallow when irrigated, which has led to the assumption that Italian ryegrass has a shallow root system. However, the fine, fibrous root system extends over 3 feet (1 m) deep on nonirrigated sites [7,52,55]. RAUNKIAER LIFE FORM : Therophyte REGENERATION PROCESSES : Italian ryegrass regenerates by seed. It is self-incompatible [39]. Seeds are probably dispersed by animals. Two cultivars (`Tribune' and `Lemtal') had higher germination rates 6 months after harvest (95 percent) than 3 weeks after harvest (50 percent), indicating some degree of dormancy immediately after harvest [32]. Seeds germinate rapidly without pretreatment [29]. Germination rates are high; 2-week germination was 80 percent under summer day/night temperatures (86/62 degrees Fahrenheit [30/17 deg C]), 76 percent under spring and fall temperatures (74/50 degrees Fahrenheit [23/10 deg C]), and 71 percent under winter temperatures (62/39 degrees Fahrenheit [17/4 deg C]) [1]. Italian ryegrass is unlikely to form a substantial seedbank because seeds germinate readily [50]. Thompson and Grime [60] place Italian ryegrass in the transient seedbank category; seeds are present only for a short time in the summer and fall. Where high soil temperatures are associated with intermediate soil moisture, viable seed is depleted through germination [51]. However, seed dormancy is induced when seeds are buried in cold, wet soil. Dormancy in buried seed did not reach maximum levels until 120 days after burial [51]. The longevity of buried Italian ryegrass seed is not known. Italian ryegrass tillers profusely [7,29]. SITE CHARACTERISTICS : Italian ryegrass grows in a wide range of soil types except for excessively drained or very poorly drained soils [25]. It requires medium to high soil fertility in order to persist on a site [53]. Italian ryegrass is intolerant of hot, dry weather. It can survive short periods of flooding if well established [53]. Italian ryegrass is reported to grow at less than 3,280 (1,000 m) in California [31], at 6,400 feet (1,350 m) in Utah, 6,500 feet (1,380 m) in Montana, and 4,000 to 8,000 feet (1,220-2,440) in Colorado [13]. SUCCESSIONAL STATUS : Italian ryegrass is a shade intolerant species. In a reciprocal transplant study between the California annual grasslands and an adjacent coast live oak (Quercus agrifolia) woodland, Italian ryegrass disappeared after 1 year of shading by the oak canopy. The canopy did not inhibit germination, but seedling survival was poor. Italian ryegrass was the most shade-sensitive herbaceous species in the study [42]. Italian ryegrass generally increased in cover with removal of blue oak (Q. douglasii) in woodlands and savannahs in the northern Sierra Nevada foothills [37]. In portions of the California annual grasslands, three species frequently coexist: wild oat (Avena fatua), soft chess (Bromus hordeaceus), and Italian ryegrass. Wild oat retains dominance but is unable to exclude the other two species. Italian ryegrass has the smallest seeds but overcomes this disadvantage with rapid growth [24]. In the Pampean grasslands of Argentina, postagricultural succession was observed for 5 years. Italian ryegrass was not present the first year and was not planted, but occurred the second year with 5.6 percent cover and increased to 42.8 percent cover by the fifth year. As Italian ryegrass became more homogeneously distributed, plant diversity decreased. The thick litter of Italian ryegrass may have inhibited other species [15]. In some ecosystems, Italian ryegrass is succeeded by perennial herbaceous species and shrubs. Italian ryegrass was initially prominent where introduced onto sites disturbed by the 1980 eruption of Mount St. Helens. However, the native, perennial colonizers fireweed (Epilobium angustifolium) and western pearlyeverlasting (Anaphalis margaritacea) soon became dominant [26]. Coyotebrush (Baccharis pilularis) invades California annual grasslands if grazing ceases and suppresses Italian ryegrass [34,43]. In May in the Santa Cruz Mountains, open grasslands contained 340 grams per square meter Italian ryegrass, but 2- to 3-year-old coyotebrush stands contained only 2 grams per square meter, and 9-year-old coyotebrush stands contained no Italian ryegrass [34]. SEASONAL DEVELOPMENT : In California, Italian ryegrass germinates with the onset of the fall rainy season [24], generally when temperatures dip below 50 degrees Fahrenheit (10 deg C) [10]. Growth is initially rapid, slows in the winter, then increases again in the spring [7,24]. Spring growth does not occur until the mean daily temperature rises above 50 degrees Fahrenheit (10 deg C) for several days, usually in late February in southern California. No growth occurs until March above 2,500 feet (760 m) [10]. Although aboveground growth slows in the winter, Italian ryegrass roots continue to grow. In mid-January in California, roots averaged 8 inches (20 cm) deep, and in early March roots averaged 12 inches (30 cm) deep while seedlings were still in the two- to three-tiller stage. By mid-April, roots were 23 inches (58 cm) deep and most tillers had been produced. Italian ryegrass roots excavated in July were 56 inches (142 cm) deep [52]. Italian ryegrass begins drying in late April in California [52]. In 1960 near Berkeley, maximum Italian ryegrass biomass occurred in late May [28]. In Colorado, anthesis begins in June and ends in July. In Montana, it begins in May and ends in July [13].


SPECIES: Lolium multiflorum
FIRE ECOLOGY OR ADAPTATIONS : Natural fires in Italian ryegrass stands are most likely to occur during the dry season when Italian ryegrass has already produced seed and dried out. Dense stands of dry Italian ryegrass burn readily [23,45]. FIRE REGIMES : Find 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". POSTFIRE REGENERATION STRATEGY : Tussock graminoid Ground residual colonizer (on-site, initial community)


SPECIES: Lolium multiflorum
IMMEDIATE FIRE EFFECT ON PLANT : Fire probably kills Italian ryegrass. Seeds may survive fire. DISCUSSION AND QUALIFICATION OF FIRE EFFECT : NO-ENTRY PLANT RESPONSE TO FIRE : Italian ryegrass generally decreases after fire. A California annual grassland site on the coastal foothills near Berkeley burned in July. Forbs generally increased and grasses decreased in the first growing season after the fire. Burned sites produced lower Italian ryegrass yields than unburned sites. Italian ryegrass height was significantly lower the year after the fire on burned sites than unburned sites [30]: Average Height (Inches) Dec 1 Feb 20 May 1 Burned 2.4 3.5 13.7 Unburned 3.7 6.9 16.1 A March 5 fire on a Georgia old field resulted in a significant (P<0.05) decrease in Italian ryegrass yield. The control produced 98.4 grams per square meter and the burned area produced 47.4 grams per square meter in the summer following the fire [46]. Italian ryegrass was present (0.1% cover) after a July fire in San Bernardino County, California. The prefire community, dominated by brittle bush (Encelia farinosa), had not burned for 21 years and did not contain Italian ryegrass [65]. The seed source for the postfire population of Italian ryegrass was not described. DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : NO-ENTRY FIRE MANAGEMENT CONSIDERATIONS : For years Italian ryegrass has been the most commonly used species for controlling erosion on burned chaparral sites, especially in northern California and coastal areas. Seed is usually broadcast aerially in the fall following the fire but preceding the winter rains. Italian ryegrass has reliable germination, rapid early growth, a short life span, abundant fibrous roots, inexpensive seed, and broad site adaptability [57]. However, the wisdom of ryegrass seeding has been questioned for decades, and recent literature indicates that postfire seeding of Italian ryegrass may cause more harm than good. The purpose of the seeding is to control erosion which is often severe during winter rains on steep slopes in California. However, studies have shown that the seeding is not effective at controlling erosion the first year and may even increase erosion in succeeding years. In addition, Italian ryegrass outcompetes the recovering native vegetation and may increase the fire hazard. The controversy is reviewed by Barro and Conard [2] and Gautier [19], and is summarized here. Several studies have shown that erosion was not controlled, and even increased, with Italian ryegrass seeding [23,57]. Erosion was greater on seeded sites than on unseeded sites of the 1985 Las Pilitas Fire in the Santa Lucia Range, Monterey County, California. Researchers found that pocket gopher activity was greater on seeded sites and was the cause of the increased erosion [57]. Nadkarni and Odion [45] suggest that as Italian ryegrass declines, vegetative cover on seeded sites may actually be less than cover on unseeded sites, and thus erosion may be greater. After the Marble-Cone Fire in the Santa Lucia Range, heavy rains in January washed 1.2 to 3.1 inches (3-8 cm) of surface soil from slopes greater than 20 percent. The erosion occurred before seeded Italian ryegrass had formed an effective cover [23]. Winter rains are often not sufficient for Italian ryegrass germination until December or January when the daily temperature is too cool for adequate growth. A wetting agent applied to the soil surface during the seeding may encourage earlier germination [11]. Seeding Italian ryegrass may have long-term detrimental effects on chaparral communities because Italian ryegrass interferes with native species regeneration. On sites seeded with Italian ryegrass, the seedbank becomes depleted of fire-following species because they may germinate but do not establish [45]. After Italian ryegrass dies out it often leaves behind a thinned out chaparral with considerably fewer nonsprouting species such as wedgeleaf ceanothus (Ceanothus cuneatus) than in areas without Italian ryegrass seeding [7]. In seeded plots in burned chaparral in the Santa Ynez Mountains, California, there was a 40 percent reduction in species diversity compared with unseeded plots. The predominant native Amador rushrose (Helianthemum scoparium) was less dense in the seeded treatment, and two other species usually found (hoaryleaf ceanothus [C. crassifolius] and common turricula [Turricula parryi]) were absent from the seeded plots. The fire-annual yellow whisperingbells (Emmenanthe penduliflora) had over 50 percent less cover on seeded plots than unseeded plots at one site in southern California [5]. The first year following the Las Pilitas Fire in the Santa Lucia Mountains, Italian ryegrass interfered with the regeneration of lupine (Lupinus spp.), lotus (Lotus spp.), and chamise (Adenostoma fasciculatum) [57]. One year after fire in chaparral in the Santa Monica Mountains, California, Italian ryegrass cover was negatively correlated with herbaceous species and with island ceanothus (Ceanothus megacarpus) [9]. Because of the ability of Italian ryegrass to compete well with woody species, it is recommended for seeding of fire breaks within chaparral communities [22]. Italian ryegrass restricts tree regeneration where seeded on burned forested sites. Italian ryegrass interfered with the regeneration of sugar pine (Pinus lambertiana) and Coulter pine (P. coulteri) seedlings after the Marble-Cone Fire [23]. Two years after fire on the Stanislaus National Forest, California, postfire regeneration of ponderosa pine (P. ponderosa) was absent where Italian ryegrass cover was greater than 40 percent [9]. An additional detrimental effect of postfire seeding is that dense stands of Italian ryegrass burn readily, and early recurring fire is destructive to regenerating shrubs [67]. The natural fire interval in chaparral is about 10 to 100 years [69]. An August 1979 fire on Otay Mountain, San Diego County, California, was seeded with Italian ryegrass. The year had near-record precipitation so Italian ryegrass growth was exceptional. In July another fire occurred in the areas seeded with Italian ryegrass. This second fire killed nearly all seedlings of explorer's bush (C. oliganthus), and chamise was reduced by up to 97 percent. Mission manzanita (Xylococcus bicolor), a postfire sprouter, suffered substantial mortality. It is believed that such an early return fire causes drastic shifts in species composition [67]. In the Santa Ynez Mountains a July fire burned into seeded areas but not unseeded areas 2 years after the original fire [45]. After fire in grasslands containing Italian ryegrass, grazing should be delayed or reduced to allow Italian ryegrass to recover [30].


SPECIES: Lolium multiflorum
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Beyers, Jan L.; Wakeman, Carla; Conard, Susan G. 1993. Effects of seeding chaparral burns with annual ryegrass on herbaceous plant cover and species diversity. In: Bulletin of the Ecological Society of America (Supplement). 74(2): 163. [Abstract]. [22948] 6. Biswell, H. H. 1956. Ecology of California grasslands. Journal of Forestry. 9: 19-24. [11182] 7. Biswell, Harold H. 1974. Effects of fire on chaparral. In: Kozlowski, T. T.; Ahlgren, C. E., eds. Fire and ecosystems. New York: Academic Press: 321-364. [14547] 8. Charmet, G.; Balfourier, F. 1994. Isozyme variation and species relationships in the Lolium L. (ryegrasses, Graminaceae). Theoretical and Applied Genetics. 87(6): 641-649. [25202] 9. Conard, S. G.; Regelbrugge, J. C.; Wills, R. D. 1991. Preliminary effects of ryegrass seeding on postfire establishment of natural vegetation in two California ecosystems. In: Andrews, Patricia L.; Potts, Donald F., eds. 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