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SPECIES:  Urtica dioica

Introductory

SPECIES: Urtica dioica
AUTHORSHIP AND CITATION : Carey, Jennifer H. 1995. Urtica dioica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://www.fs.usda.gov/database/feis/plants/forb/urtdio/all.html [].
ABBREVIATION : URTDIO SYNONYMS : Urtica gracilis Ait. [13,24,25] Urtica holosericea Nutt. [53] Urtica procera Muhl. [13,54] SCS PLANT CODE : URDI URDID URDIG URDIH COMMON NAMES : stinging nettle American stinging nettle European stinging nettle hoary nettle TAXONOMY : The currently accepted scientific name for stinging nettle is Urtica dioica L. (Urticaceae) [15,17,21,28,49]. Urtica dioica is a polymorphic complex in North America with a confusing taxonomic history; many varieties and subspecies have been described including an introduced subspecies from Europe. Although formerly separated into four species [13], most recent authors agree that the North American plants cannot be distinguished at the species level from each other and from European plants. The following three subspecies are currently recognized [3,17,21,28,51]: Urtica dioica subsp. dioica (European stinging nettle) Urtica dioica subsp. gracilis (Ait.) Selander (American stinging nettle, California nettle) Urtica dioica subsp. holosericea (Nutt.) Thorne (hoary nettle) LIFE FORM : Forb FEDERAL LEGAL STATUS : No special status OTHER STATUS : NO-ENTRY

DISTRIBUTION AND OCCURRENCE

SPECIES: Urtica dioica
GENERAL DISTRIBUTION : American stinging nettle is the most common subspecies in temperate North America and occurs throughout Canada and much of the United States.  In the East and Midwest, American stinging nettle occurs as far south as Virginia, Missouri, and Kansas; in the West, it occurs south along the coast to central California and south in the Rocky Mountains to Mexico.  European stinging nettle occurs primarily along the Atlantic Coast from Newfoundland south to Georgia and Alabama.  It is recently adventive westward in Missouri, Oklahoma, Oregon, and Alaska.  Hoary nettle is native to the western United States.  It occurs from eastern Washington south through California to Mexico, east to northern Arizona and extreme northwestern Colorado, and north to western Wyoming and southwestern Montana [51]. ECOSYSTEMS :    Stinging nettle probably occurs in most ecosystems. STATES :      AL  AK  AZ  AR  CA  CO  CT  DE  GA  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  DC  AB      BC  MB  NB  NF  NT  NS  ON  PE  PQ  SK      YT  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 :    K002  Cedar-hemlock-Douglas-fir forest    K005  Mixed conifer forest    K011  Western ponderosa forest    K012  Douglas-fir forest    K013  Cedar-hemlock-pine forest    K030  California oakwoods    K037  Mountain-mahogany-oak scrub    K093  Great Lakes spruce-fir forest    K095  Great Lakes pine forest    K096  Northeastern spruce-fir forest    K097  Southeastern spruce-fir forest    K098  Northern floodplain forest    K102  Beech-maple forest    K113  Southern floodplain forest SAF COVER TYPES :     63  Cottonwood    222  Black cottonwood-willow    228  Western redcedar    229  Pacific Douglas-fir    230  Douglas-fir-western hemlock    234  Douglas-fir-tanoak-Pacific madrone    237  Interior ponderosa pine    243  Sierra Nevada mixed conifer    244  Pacific ponderosa pine-Douglas-fir    245  Pacific ponderosa pine    246  California black oak    249  Canyon live oak    250  Blue oak-foothills pine    255  California coast live oak SRM (RANGELAND) COVER TYPES :    201  Blue oak woodland    202  Coast live oak woodland    203  Riparian woodland    217  Wetlands    409  Tall forb    413  Gambel oak    422  Riparian    805  Riparian HABITAT TYPES AND PLANT COMMUNITIES : Stinging nettle is a common understory component of riparian communities [30,50,52].  In the Santa Ana Mountains along the southern California Coast, American stinging nettle occurs in the understory of a riparian woodland dominated by California sycamore (Platanus racemosa), white alder (Alnus rhombifolia), and red willow (Salix laevigata) [48].  In Kern County, California, hoary nettle is abundant in the understory of a Fremont cottonwood (Populus fremontii), Pacific willow (Salix lasiandra), and red willow community [23].  In Montana, American stinging nettle occurs in a western redcedar (Thuja plicata) community in a ravine dissected by spring run-off channels [18]. Stinging nettle occurs in and adjacent to marshes and meadows.  In North Dakota, stinging nettle occurs in a sedge (Carex spp.)-dominated zone between an emergent marsh and upland meadow [29]. Stinging nettle occurs in moist forest communities in the southern Appalachian Mountains [4].

MANAGEMENT CONSIDERATIONS

SPECIES: Urtica dioica
IMPORTANCE TO LIVESTOCK AND WILDLIFE : The wildlife food value of stinging nettle is listed as poor [10], probably because of stinging hairs on the foliage.  Stinging nettle provides cover for small animals [10,16,42]. PALATABILITY : Stinging nettle is unpalatable to livestock [10]. NUTRITIONAL VALUE : Stinging nettle is very nutritious.  Stinging nettle hay contains 21 to 23 percent crude protein, 3 to 5 percent crude fats, 35 to 39 percent non-nitrogen extracts, 9 to 21 percent crude fiber, and 19 to 29 percent ash.  Amino acids in dehydrated stinging nettle meal are nutritionally superior to those of dehydrated alfalfa (Medicago sativa) meal [1]. COVER VALUE : Mallards and gadwalls prefer tall, dense nesting cover provided by graminoids and herbaceous vegetation including stinging nettle [42]. Stinging nettle is a component of roughs which are good cover for sharp-tailed grouse in Wisconsin [16].  Although listed as generally poor wildlife cover by Dittberner and Olson [10], stinging nettle cover is listed as fair for small nongame birds and mammals in Utah. VALUE FOR REHABILITATION OF DISTURBED SITES : Stinging nettle may be tolerant of heavy metals.  It is an abundant species on metal-contaminated soil on the floodplain of a former Rhine River estuary in the Netherlands [31]. OTHER USES AND VALUES : Boiled stinging nettle leaves are edible and can be substituted for spinach [1,11]. Stinging nettle fibers were used by Native Americans in the Northwest to make twine, fishing nets, and rope.  Stinging nettle has many medicinal uses [45]. OTHER MANAGEMENT CONSIDERATIONS : Stinging nettle is considered a weedy, invasive species.  It is listed as a noxious weed in several Canadian provinces.  Stinging nettle hairs are irritating to human skin, and the pollen is a major contributor to summer hay fever [1]. When distributed through the soil by disturbance such as mechanical cultivation, stinging nettle rhizomes can establish dense new colonies. However, repeated plowing will eliminate stinging nettle.  When mowed, stinging nettle sends up numerous bushy shoots [1]. Spraying with 2,4-D herbicide substantially reduced stinging nettle cover in a central Wisconsin marsh [19]. Stinging nettle is used by foresters as an indicator of high soil fertility [38]. Insects, micro-organisms, and viruses associated with stinging nettle are listed [1].

BOTANICAL AND ECOLOGICAL CHARACTERISTICS

SPECIES: Urtica dioica
GENERAL BOTANICAL CHARACTERISTICS : Stinging nettle is an erect, perennial, rhizomatous forb which forms dense clonal patches.  Stout stems grow 3.3 to 6.6 feet (1-2 m) tall. Leaves, stems, and flowers are sparsely to moderately covered with stinging hairs.  Two subspecies, American stinging nettle and hoary nettle, are native; the third subspecies in North America, European stinging nettle, was introduced in the mid-1800's.  American stinging nettle and hoary nettle are predominantly monoecious whereas European stinging nettle is typically dioecious.  The fruit is an achene [1,51]. Stinging nettle has both epigeal and shallow subterranean rhizomes [35]. RAUNKIAER LIFE FORM : Hemicryptophyte REGENERATION PROCESSES : Stinging nettle reproduces vegetatively and by seed. Stinging nettle produces abundant seed.  Plants growing in the shade produce approximately 500 to 5,000 seeds per shoot and plants growing in full sunlight produce 10,000 to 20,000 seeds per shoot.  Seeds remain on the plant until frost when they fall to the ground.  Seeds are not dormant and can germinate 5 to 10 days after maturity [1].  Buried stinging nettle seeds persist an undetermined length of time in the seedbank [7,26,33,34,44].  Stinging nettle seedlings emerged from unflooded substrate samples collected from the Delta Marsh, Manitoba [33].  Stinging nettle seeds, mostly buried less than 2 inches (5 cm) deep, occurred in the seedbanks of three forest communities in Idaho [26].  Stinging nettle seedlings emerged from soil samples collected from a ponderosa pine (Pinus ponderosa)/common snowberry (Symphoricarpos albus) habitat type in Washington.  April collections contained 48 stinging nettle seeds per square foot (533/sq m) and October collections contained 6 seeds per square foot (67/sq m).  Most stinging nettle seeds were buried less than 4 inches (10 cm) deep, but some were present to 10 inches (25 cm) [34].  Stinging nettle seeds have germinated in the greenhouse after 10 years of storage [1]. Stinging nettle spreads and reproduces vegetatively by rhizomes. Seedlings initiate vegetative spread in the first growing season.  A rhizome planted in late summer can spread into an 8.2 foot (2.5 m) diameter area by the following year [1]. Stinging nettle has a strong shoot thrust.  The ability to generate mechanical force enables the plant to extend its shoots vertically into dominant aerial positions [6]. SITE CHARACTERISTICS : Stinging nettle occurs in moist sites along streams, coulees, and ditches, on mountain slopes, in woodland clearings, and in disturbed areas.  Stinging nettle generally grows on deep, rich soils [1,51]. American stinging nettle occurs from sea level to subalpine elevations. Hoary nettle occurs from sea level to 10,000 feet (3,000 m) elevation in the southern part of its range and from 2,300 to 6,600 feet (700-2,000 m) elevation in the northern part of its range [51].  Stinging nettle persists in northern climates, spreading vegetatively rather than by seed [40]. Stinging nettle occurs both in wetlands and in uplands.  It is a facultative wetland species [36].  Stinging nettle is present in the seasonally flooded emergent zone of oxbow lakes along the Connecticut River [22].  Persistent flooding kills stinging nettle [20]. SUCCESSIONAL STATUS : Stinging nettle is probably intermediate in shade tolerance.  It occurs and produces seed in shady habitats but produces more seed in full sun [1]. Stinging nettle establishes colonies from which other plants are virtually excluded.  Competition from grass may limit the spread of stinging nettle clones [1] Stinging nettle invades disturbed sites.  It invades forest plantations in Great Britain when bracken fern (Pteridium aquilinum) is artificially removed [5].  Stinging nettle colonizes wetland sites when water levels drop [20,33].  It is an increaser on periodically flooded areas along Idaho streams [37]. SEASONAL DEVELOPMENT : Stinging nettle sends new shoots up each year from perennating buds on rhizomes.  Maximum root development occurs in the spring prior to flowering.  American stinging nettle flowers from late May to October, European stinging nettle flowers from June to October, and hoary nettle flowers from July to October.  In northern areas, flowering is condensed into a shorter time period, ending in late August [1,51].

FIRE ECOLOGY

SPECIES: Urtica dioica
FIRE ECOLOGY OR ADAPTATIONS : Stinging nettle survives fire by sprouting from rhizomes.  Removal of litter by fire may encourage stinging nettle growth and provide suitable germination sites for seed.  However, frequent fire during the growing season may reduce stinging nettle [43]. 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 :    Rhizomatous herb, rhizome in soil    Ground residual colonizer (on-site, initial community)    Initial-offsite colonizer (off-site, initial community)

FIRE EFFECTS

SPECIES: Urtica dioica
IMMEDIATE FIRE EFFECT ON PLANT : Stinging nettle is probably top-killed by fire.  Perennating buds on shallow rhizomes probably survive low-severity fire. DISCUSSION AND QUALIFICATION OF FIRE EFFECT : NO-ENTRY PLANT RESPONSE TO FIRE : Stinging nettle regenerates from buried rhizomes and/or seed after fire. Stinging nettle bloomed during the first postfire growing season on a ravine site in western Montana that burned in mid-July.  Although stinging nettle thrives on disturbance, its rate of spread after the fire on this site may have been slowed by competition from orchard grass (Dactylis glomerata) [8]. One year after a wildfire in northern Utah, stinging nettle was present at low frequency on plots in a burned Gambel oak (Quercus gambelii) brush community but was not present on adjacent unburned plots [30]. In southern California, large amounts of sediment were deposited in a riparian zone after a July fire in a riparian forest dominated by coast live oak (Q. agrifolia), white alder, and California sycamore.  Stinging nettle emerged from the sediment and was a common species on lower and middle terraces in the riparian zone during the 3 years following the fire [9]. Stinging nettle occurred in a central Wisconsin marsh dominated by goldenrod (Solidago spp.), butter-and-eggs (Linaria vulgaris), white meadowsweet (Spiraea alba), and grasses.  Fire was prescribed on two sites in the spring 1 week after snowmelt.  Approximately 96 percent of the dry surface fuels were eliminated.  Vegetation was inventoried during the growing seasons before and after the fires.  Stinging nettle prefire and postfire covers are as follows [19]: Prefire cover Postfire cover Site 1              2.0%      1.8% Site 2             <0.5%      2.5% Stinging nettle shoot density and biomass after fire depends on the season of burn.  Stinging nettle shoots per square meter and biomass measured the first growing season after each fire in a common reed (Phragmites australis) stand in Delta Marsh, Manitoba, are as follows:       Density                         Biomass               (nonseedling shoots/sq m)             (grams/sq m) Control          6.7 36.2 Summer fire 18.4 33.9 Fall fire  4.9 10.3 Spring fire 18.8 52.9 Stinging nettle biomass was less than in the control the first growing season after the fall fire.  The authors suggest that the stinging nettle rhizome buds may have succumbed to winterkill after the fall fire because there were no dead standing canes to trap snow and insulate the soil.  Stinging nettle biomass was greater than in the control in the first growing season after the spring fire.  Stinging nettle is capable of fast growth and, with the removal of common reed litter by fire, was able to compete with the common reed.  Stinging nettle biomass did not differ substantially from the control 1 year after the summer fire. There were more shoots per meter after the summer fire but the shoots were smaller than in the control, possibly because resources were depleted by regrowth immediately after the summer fire [43]. Stinging nettle seedlings established at a density of 6.9 seedlings per square foot (76.8/sq m) 1 month after the summer fire.  Only a few seedlings established after the fall and spring fires [43].  DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : Hamilton's Research Papers (Hamilton 2006a, Hamilton 2006b)and Metlen and others' Research Project Summary provide information on prescribed fire and postfire response of many plant species including stinging nettle. FIRE MANAGEMENT CONSIDERATIONS : NO-ENTRY

References for species: Urtica dioica


1. Bassett, I. J.; Crompton, C. W.; Woodland, D. W. 1977. The biology of Canadian weeds. 21. Urtica dioica L. Canadian Journal of Plant Science. 57: 491-498. [24185]
2. 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. [434]
3. Boufford, David E. 1992. Urticaceae: Nettle family. In: A new flora for Arizona in preparation. In: Journal of the Arizona-Nevada Academy of Science. 26(1): 42-45. [21488]
4. Brown, Dalton Milford. 1941. Vegetation of Roan Mountain: a phytosociological and successional study. Ecological Monographs. 11: 61-97. [23349]
5. Cadbury, C. J. 1976. Botanical implications of bracken control. Botanical Journal of the Linnean Society. 73: 285-294. [9621]
6. Campbell, B. D.; Grime, J. P.; Mackey, J. M. L. 1992. Shoot thrust and its role in plant competition. Journal of Ecology. 80: 633-641. [21227]
7. Champness, Stella S.; Morris, Kathleen. 1948. The population of buried viable seeds in relation to contrasting pasture and soil types. Journal of Ecology. 36: 149-173. [20023]
8. Crane, M. F.; Habeck, James R.; Fischer, William C. 1983. Early postfire revegetation in a western Montana Douglas-fir forest. Res. Pap. INT-319. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 29 p. plus chart. [710]
9. 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. [13883]
10. Dittberner, Phillip L.; Olson, Michael R. 1983. The plant information network (PIN) data base: Colorado, Montana, North Dakota, Utah, and Wyoming. FWS/OBS-83/86. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 786 p. [806]
11. Elias, Thomas S.; Dykeman, Peter A. 1982. Field guide to North American edible wild plants. [Place of publication unknown]: Outdoor Life Books. 286 p. [21103]
12. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905]
13. Fernald, Merritt Lyndon. 1950. Gray's manual of botany. [Corrections supplied by R. C. Rollins]. Portland, OR: Dioscorides Press. 1632 p. (Dudley, Theodore R., gen. ed.; Biosystematics, Floristic & Phylogeny Series; vol. 2) [14935]
14. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998]
15. 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. [20329]
16. Grange, Wallace B. 1948. The realtion of fire to grouse. In: Wisconsin grouse problems. Federal Aid in Wildlife Restoration Project No. 5R. Pub. 328. Madison, WI: Wisconsin Conservation Department: 193-205. [15908]
17. Great Plains Flora Association. 1986. Flora of the Great Plains. Lawrence, KS: University Press of Kansas. 1392 p. [1603]
18. Habeck, James R. 1963. The composition of several climax forest communities in the Lake McDonald area of Glacier National Park. Proceedings of the Montana Academy of Sciences. 23: 37-44. [6532]
19. Halvorsen, Harvey H.; Anderson, Raymond K. 1983. Evaluation of grassland management for wildlife in central Wisconsin. In: Kucera, Clair L., ed. Proceedings, 7th North American prairie conference; 1980 August 4-6; Springfield, MO. Columbia, MO: University of Missouri: 267-279. [3228]
20. Haslam, S. M. 1971. Community regulation in Phragmites communis Trin. I. Monodominant stands. Journal of Ecology. 59: 65-73. [16677]
21. Hickman, James C., ed. 1993. The Jepson manual: Higher plants of California. Berkeley, CA: University of California Press. 1400 p. [21992]
22. Holland, Marjorie M.; Burk, C. John. 1990. The marsh vegetation of three Connecticut River oxbows: a ten-year comparison. Rhodora. 92(871): 166-204. [14521]
23. Holland, Robert F.; Roye, Cynthia L. 1989. Great Valley riparian habitats and the National Registry of Natural Landmarks. In: Abell, Dana L., technical coordinator. Proceedings of the California riparian systems conference: Protection, management, and restoration for the 1990's; 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: 69-73. [13511]
24. Hulten, Eric. 1968. Flora of Alaska and neighboring territories. Stanford, CA: Stanford University Press. 1008 p. [13403]
25. Kearney, Thomas H.; Peebles, Robert H.; Howell, John Thomas; McClintock, Elizabeth. 1960. Arizona flora. 2d ed. Berkeley, CA: University of California Press. 1085 p. [6563]
26. 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. [3961]
27. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. [1384]
28. Larson, Gary E. 1993. Aquatic and wetland vascular plants of the Northern Great Plains. Gen. Tech. Rep. RM-238. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 681 p. [22534]
29. Martz, Gerald F. 1967. Effects of nesting cover removal on breeding puddle ducks. Journal of Wildlife Management. 31(2): 236-247. [16284]
30. McKell, Cyrus M. 1950. A study of plant succession in the oak brush (Quercus gambelii) zone after fire. Salt Lake City, UT: University of Utah. 79 p. Thesis. [1608]
31. Otte, M. L.; Wijte, A. H. B. M. 1993. Environmental variation between habitats and uptake of heavy metals by Urtica dioica. Environmental Monitoring and Assessment. 28(3): 263-275. [24187]
32. Padgett, Wayne G.; Youngblood, Andrew P.; Winward, Alma H. 1989. Riparian community type classification of Utah and southeastern Idaho. R4-Ecol-89-01. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Region. 191 p. [11360]
33. Pederson, Roger L. 1981. Seed bank characteristics of the Delta Marsh, Manitoba: applications for wetland management. In: Richardson, B., ed. Midwest conference on wetland values and management: Selected proceedings; 1981 June 17-19; St. Paul, MN. Minneapolis, MN: Freshwater Society: 61-69. [24016]
34. 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. [16219]
35. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. [2843]
36. Reed, Porter B., Jr. 1988. National list of plant species that occur in wetlands: Alaska (Region A). Biological Report 88(26.11). Washington, DC: U.S Department of the Interior, Fish and Wildlife Service. In cooperation with: National and Regional Interagency Review Panels. 86 p. [9328]
37. Rosentreter, Roger. 1992. High-water indicator plants along Idaho waterways. In: Clary, Warren P.; McArthur, E. Durant; Bedunah, Don; Wambolt, Carl L., compilers. Proceedings--symposium on ecology and management of riparian shrub communities; 1991 May 29-31; Sun Valley, ID. Gen. Tech. Rep. INT-289. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 18-24. [19090]
38. Schreiner, Ernst J. 1959. Production of poplar timber in Europe and its significance and application in the United States. Agric. Handb. No. 150. Washington, DC: U.S. Department of Agriculture, Forest Service. 124 p. [16479]
39. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. [23362]
40. Staniforth, Richard J.; Scott, Peter A. 1991. Dynamics of weed populations in a northern subarctic community. Canadian Journal of Botany. 69: 814-821. [14944]
41. Stickney, Peter F. 1989. Seral origin of species originating in northern Rocky Mountain forests. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT; RWU 4403 files. 10 p. [20090]
42. Swanson, George A.; Duebbert, Harold F. 1989. Wetland habitats of waterfowl in the prairie pothole region. In: van der Valk, Arnold, ed. Northern prairie wetlands. Ames, IA: Iowa State University Press: 228-267. [15218]
43. Thompson, D. J.; Shay, Jennifer M. 1989. First-year response of a Phragmites marsh community to seasonal burning. Canadian Journal of Botany. 67: 1448-1455. [7312]
44. Thompson, K.; Grime, J. P. 1979. Seasonal variation in the seed banks of herbaceous species in ten contrasting habitats. Journal of Ecology. 67: 893-921. [90]
45. Turner, Nancy Chapman; Bell, Marcus A. M. 1973. The ethnobotany of the southern Kwakiutl Indians of British Columbia. Economic Botany. 27: 257-310. [21015]
46. U.S. Department of Agriculture, Soil Conservation Service. 1994. Plants of the U.S.--alphabetical listing. Washington, DC: U.S. Department of Agriculture, Soil Conservation Service. 954 p. [23104]
47. U.S. Department of the Interior, National Biological Survey. [n.d.]. NP Flora [Data base]. Davis, CA: U.S. Department of the Interior, National Biological Survey. [23119]
48. Vogl, Richard J. 1976. An introduction to the plant communities of the Santa Ana and San Jacinto Mountains. In: Latting, June, ed. Symposium proceedings: plant communities of southern California; 1974 May 4; Fullerton, CA. Special Publication No. 2. Berkeley, CA: California Native Plant Society: 77-98. [4230]
49. 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. [2944]
50. Wheeler, Gary P.; Fancher, Jack M. 1984. San Diego County riparian systems: current threats and statutory protection efforts. In: Warner, Richard E.; Hendrix, Kathleen M., eds. California riparian systems: Ecology, conservation, and productive management. Berkeley, CA: University of California Press: 838-843. [5875]
51. Woodland, Dennis W. 1982. Biosystematics of the perennial North American taxa of Urtica. II. Taxonomy. Systematic Botany. 7(3): 282-290. [24186]
52. Zembal, Richard. 1990. Riparian habitat and breeding birds along the Santa Margarita and Santa Ana Rivers of southern California. In: Schoenherr, Allan A., ed. Endangered plant communities of southern California: Proceedings, 15th annual symposium; 1989 October 28; Fullerton, CA. Special Publication No. 3. Claremont, CA: Southern California Botanists: 98-114. [21322]
53. Munz, Philip A. 1974. A flora of southern California. Berkeley, CA: University of California Press. 1086 p. [4924]
54. 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. [7604]

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