''Asclepias sullivantii'' is a species of flowering plant in the milkweed genus, ''

Asclepias ''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 huma ...

''. Common names include prairie milkweed, Sullivant's milkweed, and smooth milkweed.''Asclepias sullivantii''.
Missouri Botanical Garden. It is native to North America, where it occurs in the central

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

.Penskar, M. R. and P. J. Higman
Special plant abstract for ''Asclepias sullivantii''.
Michigan Natural Features Inventory. Michigan State University Extension. 2000. Accessed 3 July 2012.

Description

This is a perennial herb growing from deep

rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

s. The stem is 40 centimeters to just over one meter tall. The ovate, pointed leaves are oppositely arranged and hairless. The leaves are also thick and leathery, with wavy margins, reddish midveins. They curve up on the stem. Pale to deep pinkish purple flowers are borne in rounded clusters from the leaf axils. The fruit is a greenish follicle. The flowers are insect-pollinated, but the plant often reproduces vegetatively via the rhizome. This species is very similar to ''

Asclepias syriaca ''Asclepias syriaca'', commonly called common milkweed, butterfly flower, silkweed, silky swallow-wort, and Virginia silkweed, is a species of flowering plant. It is native to southern Canada and much of the United States east of the Rocky Moun ...

'', the common milkweed, and the two easily hybridize. Common milkweed can be distinguished by several characters. Its blunt-tipped leaf blades have a coating of hairs on the undersides and are straight on the stem, not curving up. The flowers are smaller and more numerous, and the surface of the follicle is rougher.

Habitat

The native habitat of the plant includes

prairie Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...

and meadows. It grows in moist areas, such as river bottomland. The original range of ''Asclepias sullivantii'' was the tall grass prairie, but very little of that habitat remains because of wide spread conversion to farming. In Minnesota it is listed as threatened species, mainly because of

habitat loss Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

, and the remaining plants are found on old railroad right ways that preserve small prairie remnants. It is restricted to mesic tall grass prairies and seems to have little ability to survive degraded habitats.

Ecology

Insects that take

nectar Nectar is a viscous, sugar-rich liquid produced by Plant, plants in glands called nectaries, either within the flowers with which it attracts pollination, pollinating animals, or by extrafloral nectaries, which provide a nutrient source to an ...

from the plant include

bumblebee A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only Extant taxon, extant group in the tribe Bombini, though a few extinct r ...

s and other

bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamil ...

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder ...

ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...

flies Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwin ...

, and

butterflies Butterflies are winged insects from the lepidopteran superfamily Papilionoidea, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The oldest butterfly fossi ...

. The

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...

s of the

monarch butterfly The monarch butterfly or simply monarch (''Danaus plexippus'') is a milkweed butterfly (subfamily Danainae) in the family Nymphalidae. Other common names, depending on region, include milkweed, common tiger, wanderer, and black-veined brown. I ...

feed on the foliage. The

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

of the milkweed leaf-miner (''Liriomyza asclepiadis'') mine the leaves.

Aphid Aphids are small sap-sucking insects in the Taxonomic rank, family Aphididae. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white Eriosomatinae, woolly ...

s that can be found on the plant include the yellow milkweed aphid (''Aphis nerii''), black aphid (''Aphis rumicis''), and the green peach aphid (''Myzus persicae''). The

ruby-throated hummingbird The ruby-throated hummingbird (''Archilochus colubris'') is a species of hummingbird that generally spends the winter in Central America, Mexico, and Florida, and migrates to Canada and other parts of Eastern North America for the summer to bree ...

takes nectar.

Toxicity

Most ''Asclepias'' are toxic if consumed in large quantities due to

cardiac glycoside Cardiac glycosides are a class of organic compounds that increase the output force of the heart and decrease its rate of contractions by inhibiting the cellular sodium-potassium ATPase pump. Their beneficial medical uses include treatments for ...

content.

References

{{Taxonbar, from=Q4803916 sullivantii Flora of Ontario Flora of the United States