Asclepias amplexicaulis

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Asclepias amplexicaulis
Asclepias amplexicaulis Gil.jpg
photo by Gil Nelson
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida - Dicotyledons
Order: Gentianales
Family: Asclepiadaceae
Genus: Asclepias
Species: A. amplexicaulis
Binomial name
Asclepias amplexicaulis
ASCL AMPL dist.jpg
Natural range of Asclepias amplexicaulis from USDA NRCS Plants Database.

Common names: Clasping Milkweed; Sand Milkweed

Taxonomic notes

Asclepias is named for Asklepio, the Greek god of medicine and healing.[1]

Synonyms: none[2]

Varieties: none[2]


In general, with the Asclepias genus, these plants are perennial herbs containing milky sap. The stems are erect, spreading or decumbent and usually are simple and often solitary. The leaves are opposite to subopposite, are sometimes whorled, and rarely alternate. The flowers lobes are reflexed and are rarely erect or spreading. The filaments are elaborate arranged into five hoods forming a corona around the gynosteguim. The corona horns are present in most species.[3]

Specifically, for Asclepias amplexicaulis, there are 1 - 3 glabrous stems from a root crown, simple, stout, erect, and 40 - 100 cm tall. The leaves are opposite and usually in 4 - 6 pairs, are widely ovate to ovate-elliptic in shape, and are 8 - 15 cm long and 4 - 8 cm wide. The leaves are mucronate, crispate, auriculate-clasping, glaucous and sessile. The umbel corona is 5 - 8 mm in diameter. The horns are 1.5 times as long as the hood that are arching over the gynostegium. The follicles are erect, are 8 - 14 cm long, and are 1.2 - 2.3 cm wide.[3] The root structure is long, fleshy, and unbranched with few to none fibrous rootlets, and 18 inches to 2 feet in length.[4]

The flowers smell of cloves and roses.[2]


In the United States, it is found as north as New Hampshire and New York, then west to Kansas, south to Texas and Florida. In Florida, it’s found in south to central peninsula.[2]



Asclepias amplexicaulis is found on the upper slopes of longleaf pine-wiregrass flatwoods, and in mixed pine-hardwood habitats, open sand pine woodlands, and longleaf pine-oak-wiregrass sandhill communities. It prefers high light levels associated with open woodlands and dry sandy soils such as loamy sand. It can also appear in human disturbed areas like clearings and roadsides.

Associated species include Pinus palustris, Aristida stricta, Quercus laevis, and Baptisia lecontei.[5]


It flowers from spring to summer.[6] It has been observed flowering in April and May with peak inflorescence in May.[7][5] The hood on the flowers have been observed to range in color from a pinkish or fleshy color to a dark maroon.[8] Fruits are erect spindle-shaped pods containing many brown seeds[9] that occur in June and July.[5]

Kevin Robertson has observed this species flower within three months of burning. KMR

Seed dispersal

Seeds have a tuft of white to tan hair that allows for wind dispersal. [9] This species is thought to be dispersed by wind. [10]

Fire ecology

Asclepius amplexicaulis has been observed present in areas that are burned by prescribed fire,[5] and populations are known to persist through repeated annual burns.[11] A study also found that A. amplexicaulis occurred after a winter burn.[12]


Pollination of Asclepias is unusual. Pollen is contained in sacs (pollinia) located in the slits of the flower (stigmatic slits), when a pollinator walks across the flower head, these sacs attach to the pollinator and disperses on to another plant when the pollinator lands and walks.[1] There is no specialist insect pollinator[13], however it has been recognized by pollination ecologists to attract a large number of native bees.[14] Pollinated by Danaus plexippus (family Nymphalidae).[15]

Herbivory and toxicology

Contains a poison dangerous to humans and livestocks. Danaus plexippus larva use milkweed for food.[15] A. amplexicaulis is of special value to native bees, bumble bees, and honey bees, and supports conservation biological control through attracting predatory or parasitoid insects that prey on pest insects.[14] It is also a known host plant for the milkweed stem weevil (Rhyssomatus lineaticollis) to feed on.[13] Additionally, Asclepias amplexicaulis has been observed to host sweat bees such as Lasioglossum pilosum (family Halictidae), leafcutting bees from the Megachilidae family such as Megachile addenda and M. exilis, as well as planthoppers such as Scolops sulcipes (Dictyopharidae).

Conservation, cultivation, and restoration

A. amplexicaulis is listed as threatened by the New Hampshire Division of Forests and Lands and the Vermont Department of Fish and Wildlife Nongame and Natural Heritage Program; it is listed as a species of special concern by the Rhode Island Department of Environmental Management.[16]

Cultural use

Photo Gallery

References and notes

  1. 1.0 1.1 [[1]]Florida Native Plant Society. Accessed: March 30, 2016
  2. 2.0 2.1 2.2 2.3 Weakley, A.S. 2020. Flora of the Southeastern United States. Edition of 20 October 2020. University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
  3. 3.0 3.1 Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. Manual of the Vascular Flora of the Carolinas. 1964, 1968. The University of North Carolina Press. 97-98. Print.
  4. Ravenel, H. W. (1881). "Abnormal Habit of Asclepias amplexicaulis." Bulletin of the Torrey Botanical Club 8(8): 87-88.
  5. 5.0 5.1 5.2 5.3 Florida State University Robert K. Godfrey Herbarium database. URL: Last accessed: June 2014. Collectors: Loran C. Anderson, Robert K. Godfrey, Sidney McDaniel, R. A. Norris, Richard R. Clinebell II, Travis MacClendon, Karen MacClendon, and G. Wilder. States and Counties: Florida: Washington, Franklin, Leon, Okaloosa, Holmes, Wakulla, Calhoun, and Jackson. Georgia: Thomas.
  6. Wunderlin, Richard P. and Bruce F. Hansen. Guide to the Vascular Plants of Florida. Third edition. 2011. University Press of Florida: Gainesville/Tallahassee/Tampa/Boca Raton/Pensacola/Orlando/Miami/Jacksonville/Ft. Myers. 270. Print.
  7. Nelson, G. PanFlora: Plant data for the eastern United States with emphasis on the Southeastern Coastal Plains, Florida, and the Florida Panhandle. Accessed: 22 MAR 2019
  8. Uttal, L. J. (1955). "A Dark-hooded Variant of Asclepias Amplexicaulis." Rhodora 57(684): 336-337.
  9. 9.0 9.1 [[2]]Minnesota Wildflower. Accessed: March 30, 2016
  10. Kirkman, L. Katherine. Unpublished database of seed dispersal mode of plants found in Coastal Plain longleaf pine-grasslands of the Jones Ecological Research Center, Georgia.
  11. Robertson, K.M. Unpublished data collected from Pebble Hill Fire Plots, Pebble Hill Plantation, Thomasville, Georgia.
  12. Kush, J. S., et al. (2000). Understory plant community response to season of burn in natural longleaf pine forests. Proceedings 21st Tall Timbers Fire Ecology Conference. Fire and forest ecology: innovative silviculture & vegetation management, Tallahassee, FL, Tall Timbers Research, Inc.
  13. 13.0 13.1 [[3]]Xerces Society. Accessed: March 30, 2016
  14. 14.0 14.1 [[4]] Lady Bird Johnson Wildflower Center. Accessed: March 22, 2019
  15. 15.0 15.1 [[5]]
  16. USDA, NRCS. (2016). The PLANTS Database (, 22 March 2019). National Plant Data Team, Greensboro, NC 27401-4901 USA.