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SPECIES: Oxytropis sericea
AUTHORSHIP AND CITATION: Esser, Lora L. 1993. Oxytropis sericea. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: []. Revisions: On 1 June 2018, the common name of this species was changed in FEIS from: whitepoint locoweed to: white locoweed. The map was also added. ABBREVIATION: OXYSER SYNONYMS: NO-ENTRY NRCS PLANT CODE: OXSE COMMON NAMES: white locoweed crazyweed silky crazyweed whitepoint crazyweed whitepoint locoweed TAXONOMY: The scientific name for white locoweed is Oxytropis sericea Nutt. [40]. Recognized varieties and natural hybrids are as follows: Oxytropis sericea var. sericea [11,14,40]--This variety hybridizes with O. lambertii (Lambert crazyweed) in the western Great Plains, Rocky Mountain foothills, and Colorado [40]. Oxytropis sericea var. speciosa (Torr. & A. Gray) S.L. Welsh [40]. LIFE FORM: Forb FEDERAL LEGAL STATUS: No special status OTHER STATUS: NO-ENTRY


SPECIES: Oxytropis sericea
GENERAL DISTRIBUTION: White locoweed occurs from the Yukon Territory east to Manitoba and south to Nevada, New Mexico, and Texas [42]. It is commonly found in the Great Plains, throughout the Rocky Mountains, and in the Pacific Northwest [11,37].
Distribution of white locoweed. Map courtesy of USDA, NRCS. 2018. The PLANTS Database. National Plant Data Team, Greensboro, NC [2018, June 1] [37].

   FRES20  Douglas-fir
   FRES21  Ponderosa pine
   FRES22  Western white pine
   FRES23  Fir - spruce
   FRES25  Larch
   FRES26  Lodgepole pine
   FRES29  Sagebrush
   FRES30  Desert shrub
   FRES32  Texas savanna
   FRES35  Pinyon - juniper
   FRES36  Mountain grasslands
   FRES37  Mountain meadows
   FRES38  Plains grasslands
   FRES39  Prairie
   FRES40  Desert grasslands
   FRES44  Alpine

     AZ  CO  ID  KS  MN  MT  NE  NV  NM  ND
     OK  OR  SD  TX  UT  WA  WY  AB  BC  MB
     NT  SK  YT

    1  Northern Pacific Border
    2  Cascade 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

   K008  Lodgepole pine - subalpine forest
   K010  Ponderosa shrub forest
   K011  Western ponderosa forest
   K012  Douglas-fir forest
   K015  Western spruce - fir forest
   K016  Eastern ponderosa forest
   K017  Black Hills pine forest
   K018  Pine - Douglas-fir forest
   K020  Spruce - fir - Douglas-fir forest
   K021  Southwestern spruce - fir forest
   K022  Great Basin pine forest
   K023  Juniper - pinyon woodland
   K024  Juniper steppe woodland
   K037  Mountain-mahogany - oak scrub
   K038  Great Basin sagebrush
   K050  Fescue - wheatgrass
   K055  Sagebrush steppe
   K056  Wheatgrass - needlegrass shrubsteppe
   K063  Foothills prairie
   K064  Grama - needlegrass - wheatgrass
   K065  Grama - buffalograss

   210  Interior Douglas-fir
   212  Western larch
   215  Western white pine
   218  Lodgepole pine
   219  Limber pine
   220  Rocky Mountain juniper
   237  Interior ponderosa pine
   238  Western juniper
   239  Pinyon - juniper




SPECIES: Oxytropis sericea
IMPORTANCE TO LIVESTOCK AND WILDLIFE: Livestock: White locoweed causes locoism in all classes of livestock [12,36]. The toxin in locoweed is an indolizidine alkaloid, swainsonine, that causes chronic neurological damage [29]. Livestock must consume large amounts of white locoweed for 1 to 3 months before death occurs. Signs of poisoning will appear after 2 to 3 weeks of continuous grazing [36]. Symptoms are as follows: rough coats, nervous disorders such as trembling and paralysis, uncoordinated muscle movements, blindness, constipation, and emaciation [34]. Most cattle will readily graze white locoweed in the spring when grass is scarce. Sheep and cattle can become chemically addicted to white locoweed and will continue to graze it when grass becomes abundant. They are, however, more resistant than horses to its toxic effects [16,22]. Horses never recover once poisoned. Cattle gain weight slowly and often have abortions, while sheep have a high number of abortions after grazing white locoweed [43]. On high mountain ranges, white locoweed has been identified as a predisposing factor in high mountain brisket disease, or congestive right-sided heart failure, in cattle [22,26]. Wildlife: White locoweed is poisonous to deer and elk if consumed in large quantities [36]. White locoweed is a minor component in the diet of desert cottontails. Greatest utilization is in the spring and summer, when white locoweed is the most succulent [9]. PALATABILITY: Immature white locoweed seed pods are palatable and voluntarily selected by free-ranging cattle during the normal grazing season [22]. The reproductive heads of locoweed are preferred and readily consumed even when other forage species are abundant [29]. Palatability ratings for white locoweed from selected western states are as follows [3]: WY UT CO MT cattle fair poor poor poor sheep fair fair poor fair horses fair poor poor fair elk fair poor ---- ---- mule deer good poor ---- fair white-tailed deer ---- good ---- ---- pronghorn fair poor ---- ---- upland game birds poor poor ---- ---- waterfowl ---- poor ---- ---- small nongame birds poor poor ---- ---- small mammals ---- poor ---- ---- NUTRITIONAL VALUE: All parts of white locoweed plants are toxic, and plants are poisonous at all stages of growth. It loses little toxicity after 3 years of storage [36]. Swainsonine inhibits the enzyme alpha-mannosidase which is essential in the metabolism of glycoproteins [22]. Relative magnitude of alkaloid concentration and nutrients (percent of dry weight) in white locoweed are as follows [29]: Bloom Immature Pod Mature Pod week of grazing season 0 2 4 7 nutrient loco part alkaloid head high moderate moderate high leaf low low low low crude protein head 17.3 17.3 17.4 16.4 leaf 12.9 12.1 11.8 11.1 fiber head 26 38 41 40 leaf 32 36 36 36 water head 65 60 57 43 leaf 69 65 65 51 In a study in northwestern Utah. percent of loco heads (flowers and pods) grazed was 26 percent after the first 2 weeks of the grazing season and increased to 69 percent by the end of the 7-week grazing season [26]. Energy value and protein value for white locoweed are poor [3]. COVER VALUE: NO-ENTRY VALUE FOR REHABILITATION OF DISTURBED SITES: NO-ENTRY OTHER USES AND VALUES: NO-ENTRY OTHER MANAGEMENT CONSIDERATIONS: Locoweed poisoning of livestock is the most widespread poisonous plant problem in the western United States [26]. White locoweed increases in abundance in response to excessive grazing [16]. When there is a shortage of palatable, nonpoisonous forage, animals will consume more locoweed [34]. Eradication of white locoweed over large areas is seldom possible. Vegetation manipulation should be integrated with livestock management programs that minimize the intake of white locoweed [16]. Aversive conditioning of livestock to avoid white locoweed may be effective in reducing livestock losses [29]. A three-herd, four-pasture rotation system that involves grazing animals for 6 weeks to 2 months in July and August has reduced the risk of white locoweed intoxication in the Raft River Mountains of Utah [31]. Selective herbicide control may be necessary to reduce white locoweed [29]. Picloram, dicamba, and 2,4-D are effective on white locoweed if sprayed when plants are actively growing in early summer before they reach the bud stage [43]. An ester of 2,4-D was sprayed on white locoweed on a rangeland in northwest Utah in 1969. White locoweed established to pretreatment levels by 1978 [26]. When aerially sprayed with 2,4-D in 1981, all plants were killed on deeper soils, but some remained on shallower soils [26]. White locoweed fixes atmospheric nitrogen. It has potential to add significant amounts of nitrogen to forest sites in the Inland Northwest because of its nitrogen-fixing ability [13]. However, white locoweed seedlings compete with conifer tree seedlings on many sites [13].


SPECIES: Oxytropis sericea
GENERAL BOTANICAL CHARACTERISTICS: White locoweed is a native, perennial, leguminous forb that grows from 6 to 12 inches (15.2-30.4 cm) tall [12,43]. Leaves are 1.6 to 8 inches (4-20 cm) long [35]. Legumes are erect, oblong, or ovoid-oblong and are 0.4 to 1.0 inch (1-2.5 cm) long [35]. One plant may have many flowering stalks, each with 6 to 27 flowers [12]. Each flower produces many seeds. White locoweed has a long taproot [30]. RAUNKIAER LIFE FORM: Phanerophyte REGENERATION PROCESSES: White locoweed reproduces sexually from kidney-shaped seed. Seed pods are hairy and leatherlike [38]. Seeds have hard, impermeable seed coats and remain viable in the soil for many years. A large, dormant seed reserve is retained in the soil to permit exploitation of favorable environmental conditions [30]. SITE CHARACTERISTICS: White locoweed occurs on open, well-drained slopes of the western plains, the foothills of the Rocky Mountains, and grassy subalpine openings bordered by open wooded hillsides or coniferous forests [410,26]. It is infrequent to common on prairie uplands, streambanks, valleys, and alpine sites [35]. White locoweed occurs on sandy, gravelly, or rocky soils but grows best on sandy loams. It is tolerant of moderately saline soils and low nutrient conditions but does not tolerate water-saturated soils such as heavy clay [38]. White locoweed is drought tolerant but is not tolerant of excessive shade. It is tolerant to freezing temperatures during the growing season and competes well on nutrient-rich, deep loam on subalpine sites [30]. White locoweed has adapted a stress-tolerant survival strategy characteristic of plants in arctic and alpine habitats. It has a large seedbank that remains viable for many years. Its principal stresses are low temperatures, desiccating effects of strong winds on rocky slopes, intense solar radiation, and mineral nutrient deficiencies [30]. White locoweed thrives at medium elevations but grows at elevations up to 11,000 feet (3,708 m) in Colorado [3]. Regional elevation distributions are as follows [3,4,25]: feet meters Utah 5,800- 9,800 1,768-2,987 Colorado 3,500-11,000 1,067-3,353 Wyoming 4,000-10,500 1,219-3,201 Montana 3,000-10,000 914-3,048 Arizona 7,000- 8,000 2,134-2,439 New Mexico 7,000- 8,000 2,134-2,439 Alberta 4,500- 7,000 1,370-2,134 Common associated species not listed in Distribution and Occurrence are as follows: junegrass (Koeleria cristata), needleandthread (Stipa comata), buffalograss (Buchloe dactyloides), western wheatgrass (Pascopyrum smithii), squirreltail (Elymus elymoides), green needlegrass (S. viridula), Idaho fescue (Festuca idahoensis), Arizona fescue (F. arizonica), bluebunch wheatgrass (Pseudoroegneria spicata), muttongrass (Poa fendleriana), Kentucky bluegrass (P. pratensis), Arizona fescue (F. arizonica), Indian ricegrass (Oryzopsis hymenoides), sand dropseed (Sporobolus cryptandrus), red threeawn (Aristida longiseta), Wyoming big sagebrush (Artemesia tridentata ssp. wyomingensis), alpine sagebrush (A. scopulorum), plains prickly pear (Opuntia polyacantha), Hood's phlox (Phlox hoodii), low rabbitbrush (Chrysothamnus viscidiflorus), sedges (Carex spp.), aster (Aster spp.), daisy (Erigeron spp.), yarrow (Achillea spp.), quininebush (Garrya flavescens pallida), scarlet globemallow (Sphaeralcea coccinea), slimflower scurfpea (Psoralea tenuiflora), locoweed (Astragalus spp.), purple prairie-clover (Dalea purpurea), broom snakeweed (Gutierrezia sarothrae), dotted gayfeather (Liatrus punctata), arrowleaf balsamroot (Balsamorhiza sagittata), and grassland Indian paintbrush (Castellaja lutescens) [2,7,9,19,25,26]. SUCCESSIONAL STATUS: White locoweed is an important colonizer following disturbance on western rangelands [26]. It also occurs in climax meadow and sagebrush steppe communities. SEASONAL DEVELOPMENT: White locoweed is one of the first species to commence growth in early spring on many western rangelands. Growth begins in early April and plants remain green and succulent throughout the summer [2,28]. First bloom for white locoweed occurs in mid-June to early July. Seed dissemination begins in mid-July and lasts until mid-August [22]. The plant begins to dry in late September. Some reported dates for anthesis in some western states are as follows [3]: Utah May-July Colorado May-August Wyoming March-August Montana May-August


SPECIES: Oxytropis sericea
FIRE ECOLOGY OR ADAPTATIONS: No specific fire information was available in the literature regarding white locoweed. The seeds of this species are hard and impermeable and remain viable in the soil for many years until favorable environmental conditions arise [30]. According to Gill, seeds stored in the soil are often scarified by fire and released for germination [8]. 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: Initial-offsite colonizer (off-site, initial community)


SPECIES: Oxytropis sericea
IMMEDIATE FIRE EFFECT ON PLANT: No information was available on this topic. PLANT RESPONSE TO FIRE: No information was available on this topic. FIRE MANAGEMENT CONSIDERATIONS: No information was available on this topic.


SPECIES: Oxytropis sericea
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F. 1970. Objectionable characteristics of range plants. In: Range and wildlife habitat evaluation--a research symposium: Proceedings; 1968 May; Flagstaff; Tempe, AZ. Misc. Publ. 1147. Washington, DC: U.S. Department of Agriculture, Forest Service: 63-70. [12986] 22. Mueggler, Walter F. 1983. Variation in production and seasonal development of mountain grasslands in western Montana. Research Paper INT-316. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 16 p. [1710] 23. Mueggler, W. F.; Stewart, W. L. 1980. Grassland and shrubland habitat types of western Montana. Gen. Tech. Rep. INT-66. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 154 p. [1717] 24. Platt, Kenneth B. 1959. Plant control--some possibilities and limitations. I. The challenge to management. Journal of Range Management. 12: 64-68. [4596] 25. Pearson, G. A. 1931. 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