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SPECIES:  Asclepias incarnata


SPECIES: Asclepias incarnata
AUTHORSHIP AND CITATION : Pavek, Diane S. 1992. Asclepias incarnata. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [].
ABBREVIATION : ASCINC SYNONYMS : Asclepias pulchra Ehrh. ex Willd. SCS PLANT CODE : ASIN COMMON NAMES : swamp milkweed milkweed TAXONOMY : The currently accepted scientific name of swamp milkweed is Asclepias incarnata L. (Asclepidaceae). There is disagreement in the taxonomic literature about infrataxa treatment. Two subspecies are recognized: Asclepias incarnata ssp. incarnata [23] A. i. ssp. pulchra (Ehrh. ex Willd.) Woods. [23] Also recognized are the following variety and forms: A. i. var. incarnata f. incarnata [21] A. i. var. incarnata f. albiflora--Found only in Missouri [21] A. i. var. incarnata f. rosea Bowin--Found only in southern Ontario, Canada [18]. This report does not use infrataxa; they rarely appear in the literature. LIFE FORM : Forb FEDERAL LEGAL STATUS : No special status OTHER STATUS : NO-ENTRY


SPECIES: Asclepias incarnata
GENERAL DISTRIBUTION : Swamp milkweed is found throughout the eastern and midwestern United States and Canada. It occurs from Prince Edward Island and Maine west to southern Manitoba [20,23,21]. Swamp milkweed continues southeast through the Midwest and Great Plains to Florida [6,15,18]. Its distribution extends westward to Texas and New Mexico [2,20,24]. Six disjunct areas of its range occur in southern Idaho, Wyoming, Nevada, and north, central, and south Utah [3,26]. ECOSYSTEMS : FRES12 Longleaf - slash pine FRES13 Loblolly - shortleaf pine FRES15 Oak - hickory FRES16 Oak - gum - cypress FRES28 Western hardwoods STATES : AZ CT FL GA ID IL IN LA ME MA MI MN MO NV NH NM ND OK RI SC SD TN TX UT VT VA WI WY MB NB NS ON PE PQ BLM PHYSIOGRAPHIC REGIONS : 6 Upper Basin and Range 8 Northern Rocky Mountains 10 Wyoming Basin 11 Southern Rocky Mountains 12 Colorado Plateau 13 Rocky Mountain Piedmont 14 Great Plains KUCHLER PLANT ASSOCIATIONS : K025 Alder - ash forest K081 Oak savanna K082 Mosaic of K074 and K100 K084 Cross Timbers K089 Black Belt K090 Live oak - sea oats K091 Cypress savanna K100 Oak - hickory forest K104 Appalachian oak forest K105 Mangrove K110 Northeastern oak - pine forest K111 Oak - hickory - pine forest K112 Southern mixed forest K113 Southern floodplain forest K114 Pocosin K115 Sand pine scrub K116 Subtropical pine forest SAF COVER TYPES : 45 Pitch pine 50 Black locust 53 White oak 55 Northern red oak 57 Yellow-poplar 58 Yellow-poplar - eastern hemlock 59 Yellow-poplar - white oak - northern red oak 61 River birch - sycamore 64 Sassafras - persimmon 65 Pin oak - sweetgum 69 Sand pine 70 Longleaf pine 73 Southern redcedar 75 Shortleaf pine 79 Virginia pine 80 Loblolly pine - shortleaf pine 81 Loblolly pine - shortleaf pine 83 Longleaf pine - slash pine 84 Slash pine 87 Sweet gum - yellow-poplar 88 Willow oak - water oak - diamondleaf oak 89 Live oak 91 Swamp chestnut oak - cherrybark oak 96 Overcup oak - water hickory 97 Atlantic white cedar 101 Baldcypress 102 Baldcypress - tupelo 103 Water tupelo - swamp tupelo 104 Sweetbay - swamp tupelo - redbay 105 Tropical hardwoods 109 Hawthorn 110 Black oak 111 South Florida slash pine 222 Black cottonwood - willow 235 Cottonwood - willow 252 Paper birch SRM (RANGELAND) COVER TYPES : NO-ENTRY HABITAT TYPES AND PLANT COMMUNITIES : NO-ENTRY


SPECIES: Asclepias incarnata
IMPORTANCE TO LIVESTOCK AND WILDLIFE : Swamp milkweed foliage and stems have been reported to cause mortality in sheep. It is not known why sheep are so susceptible [7,12]. Muskrats are unaffected by swamp milkweed and readily eat the roots [23]. PALATABILITY : Milkweeds in general are not palatable to wildlife. The bitter milky juice is high in alkaloids [17]. Most animals avoid it unless forced to eat it on overgrazed pastures [17]. NUTRITIONAL VALUE : NO-ENTRY COVER VALUE : NO-ENTRY VALUE FOR REHABILITATION OF DISTURBED SITES : Swamp milkweed is currently used in Wisconsin for wetland rehabilitation [11]. It is included in commercially available seed mixes. OTHER USES AND VALUES : Swamp milkweed seeds have long hairs, called comas. Seed comas have been used as pillow and lifejacket stuffing [3,23]. Stem fibers have been suggested as substitutes for flax and hemp [3]. Young shoots, inflorescences, and leaves may be cooked with several changes of water and eaten [23]. This plant causes dermititis. OTHER MANAGEMENT CONSIDERATIONS : NO-ENTRY


SPECIES: Asclepias incarnata
GENERAL BOTANICAL CHARACTERISTICS : Swamp milkweed is an erect plant, 11 to 18 inches (0.3-0.5 m) tall, with milky sap. It has a short rootstock or caudex with shallow fibrous roots. A plant may have one to several leafy stems. Its lance-shaped, opposite leaves have short stalks. Flowers have many elaborate structures (e.g., hoods and horns) and are arranged in flesh-colored terminal umbels [23]. RAUNKIAER LIFE FORM : Hemicryptophyte REGENERATION PROCESSES : Swamp milkweed readily germinates from seed shed the previous year (50 to 88 percent germination [11]) after cold stratification, 39 degrees Fahrenheit (4 deg C), for approximately 9 months. A plant puts up an average of one stem from a short caudex and sprouts each year from this rootstock. Flowers are insect pollinated (Hymenoptera and Lepidoptera) [10]. Seeds have long hairs that facilitate wind dispersal in the fall. Swamp milkweed is self-fertile [8]. It very rarely reproduces asexually by rhizomes [8]. SITE CHARACTERISTICS : Swamp milkweed is a semiaquatic plant [3]. It occurs in a range of wet conditions from standing water to saturated soil. A riparian species, it is found on streambanks, pond shores, banks, and floodplains of lakes, waterways, marshes, swamps, and wet areas of prairies [6,13,18,21]. Additionally, it occurs in wet meadows and in low wet woods [23]. SUCCESSIONAL STATUS : Swamp milkweed is a colonizer. It has wind-dispersed seeds and can self-fertilize. SEASONAL DEVELOPMENT : Across its range, swamp milkweed begins to flower during the last week of June or the first week in July and continues until August or September [2,6,15,18,21,23]. Individual flowers remain open for about 1 week [9]. Fruits mature from August through October [2,6,15,18,21,23]. After maturation, follicles split open on one side to release seeds during October and November [23].


SPECIES: Asclepias incarnata
FIRE ECOLOGY OR ADAPTATIONS : The moist habitat of swamp milkweed discourages fire entry. Swamp milkweed is very shallowly rooted; it would most likely be killed in a fire of any severity. Adjacent communities may serve as seed sources after a fire. Swamp milkweed is a component of prairie wetlands, so it has evolved with some fire exposure. 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 : survivor species; on-site surviving root crown or caudex off-site colonizer; seed carried by wind; postfire years 1 and 2


SPECIES: Asclepias incarnata
IMMEDIATE FIRE EFFECT ON PLANT : No fire studies on this plant have been reported. A fire would kill swamp milkweed back to the caudex. In moist soil, the caudex is usually not deeply rooted. Death would depend upon fire severity. It may survive a cool fire. Late season (summer and fall) fires would have the greatest effect on this species. Since its seeds are not shed until October or November, a late season fire would kill the seed crop of the current year. DISCUSSION AND QUALIFICATION OF FIRE EFFECT : NO-ENTRY PLANT RESPONSE TO FIRE : Following a cool surface fire, swamp milkweed sprouts from the caudex and produces fruit. If plants have been killed, off-site seeds will be wind dispersed into the burned area. This seed will germinate on burned areas during the first postfire growing season, provided soil conditions are wet. Long-term response: Swamp milkweed should have no difficulties in maintaining populations. It can self-fertilize; sexual reproduction will continue, despite a reduced number of colonizing plants. Plant recovery is controlled by the severity of the fire and availability of adequately wet habitat. DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : NO-ENTRY FIRE MANAGEMENT CONSIDERATIONS : NO-ENTRY

References for species: Asclepias incarnata

1. 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]
2. Correll, Donovan S.; Johnston, Marshall C. 1970. Manual of the vascular plants of Texas. Renner, TX: Texas Research Foundation. 1881 p. [4003]
3. 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. [718]
4. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905]
5. 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]
6. Great Plains Flora Association. 1986. Flora of the Great Plains. Lawrence, KS: University Press of Kansas. 1392 p. [1603]
7. Hansen, Albert A. 1924. Robitin--a potent plant poison. Better Crops. 2(2): 22-23; 44. [29437]
8. Kephart, Susan R. 1981. Breeding systems in Asclepias incarnata L., A. syriaca L., and A. verticillata L. American Journal of Botany. 68: 226-232. [18147]
9. Kephart, Susan R. 1987. Phenological variation in flowering and fruiting of Asclepias. The American Midland Naturalist. 118(1): 64-76. [18146]
10. Kephart, Susan R.; Heiser, Charles B., Jr. 1980. Reproductive isolation in Asclepias: lock and key hypothesis reconsidered. Evolution. 34(4): 738-746. [18148]
11. Kerans, Karen. 1990. Country Wetlands Nursery Ltd. Restoration & Management Notes. 8(1): 29-31. [14513]
12. Kingsbury, John M. 1964. Poisonous plants of the United States and Canada. Englewood Cliffs, NJ: Prentice-Hall, Inc. 626 p. [122]
13. Kron, Kathleen A. 1989. The vegetation of Indian Bowl wet prairie and its adjacent plant communities. II. Checklist of vascular plants. Michigan Botanist. 28(4): 201-215. [17359]
14. 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]
15. Lakela, O. 1965. A flora of northeastern Minnesota. Minneapolis, MN: University of Minnesota Press. 541 p. [18142]
16. Lyon, L. Jack; Stickney, Peter F. 1976. Early vegetal succession following large northern Rocky Mountain wildfires. In: Proceedings, Tall Timbers fire ecology conference and Intermountain Fire Research Council fire and land management symposium; 1974 October 8-10; Missoula, MT. No. 14. Tallahassee, FL: Tall Timbers Research Station: 355-373. [1496]
17. Muenscher, W. C. 1940. Poisonous plants of the United States. New York: MacMillan Co. 266 p. [18141]
18. 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. [7606]
19. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. [2843]
20. Scoggan, H. J. 1978. The flora of Canada. Ottawa, Canada: National Museums of Canada. (4 volumes) [18143]
21. 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]
22. Shipley, B.; Parent, M. 1991. Germination responses of 64 wetland species in relation to seed size, minimum time to reproduction and seedling relative growth rate. Functional Ecology. 5(1): 111-118. [14554]
23. Steyermark, J. A. 1963. Flora of Missouri. Ames, IA: Iowa State University Press. 1725 p. [18144]
24. Tidestrom, I.; Kittell, T. 1941. A flora of Arizona and New Mexico. Washington, DC: The Catholic University of America Press. 897 p. [18145]
25. U.S. Department of Agriculture, Soil Conservation Service. 1982. National list of scientific plant names. Vol. 1. List of plant names. SCS-TP-159. Washington, DC. 416 p. [11573]
26. 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]

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