Index of Species Information

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. 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

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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]
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12. Kingsbury, John M. 1964. Poisonous plants of the United States and Canada. Englewood Cliffs, NJ: Prentice-Hall, Inc. 626 p. [122]
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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]