''Asclepias hirtella'', commonly called the tall green milkweed, is a species of flowering plant in the

milkweed ''Asclepias'' is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to humans ...

genus and dogbane family (

Apocynaceae Apocynaceae (from ''Apocynum'', Greek for "dog-away") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison Members of the ...

). It is native to Canada and the United States, where its range is concentrated in the

Midwest The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four Census Bureau Region, census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of ...

and Upper South.

Description

''Asclepias hirtella'' is a tall perennial, reaching 3 feet in height. It has many narrow, linear leaves that are produced alternately on the stem. Its flowers in lateral umbels with slender peduncles. Each stem may have 2 to 10 umbels and each umbel may have 30 to 100 flowers. The flowers lack horns and are greenish to slightly purplish in color. It flowers June through August. This species closely resembles '' Asclepias longifolia'', and it is occasionally treated to be a subspecies of it. ''Asclepias longifolia'' is restricted to the Southeastern Coastal Plain, and it differs from ''Asclepias hirtella'' in its fewer and smaller flower umbels, and its glabrous leaves.

Habitat

''Asclepias hirtella'' is found in a variety of open habitats, including areas with dry sandy soil, prairies and limestone glades,''Asclepias hirtella''
Missouri Botanical Garden It can be found in both wet and dry conditions, and it prefers open habitats with full sun. This species is a component of high-quality grassland communities, although it can be found in and disturbed conditions as well. It is considered to be uncommon throughout much of its range.

Distribution

''Asclepias hirtella'' is native to West Virginia, Ohio, Michigan and Wisconsin to northern Iowa, Kansas and Oklahoma to southwestern Kentucky. It is a prairie species native to 13 US states and one Canadian province, but is becoming rare or declining in numbers in parts of its native range. ''A. hirtella '' is rare in Minnesota and listed as a threatened species in that state, where it occurs in the south eastern corner in mesic prairie habitats.

References

{{Taxonbar, from=Q18078347

hirtella ''Hirtella'' is a genus of 110 species of woody trees in family Chrysobalanaceae. It was first described as a genus by Linnaeus in 1753. ''Hirtella'' naturally occurs in tropical forests throughout Latin America, the West Indies, southeast Afri ...