. Botanical and vegetation survey of Carter County, Montana, Bureau of Land Management-administered lands . Botany; Rare plants. Asclepias ovalifolia Decaisne O VALLE AF MILKWEED Milkweed Family (Asclepiadaceae) CONSERVATION STATUS U. S. Fish and Wildlife Service: None Bureau of Land Management: Watch. Montana Natural Heritage Program: G5? S1; Demonstrably secure globally, but may be critically imperiled in Montana where it is extremely rare. DESCRIPTION: Ovalleaf milkweed is a rhizomatous perennial with solitary (occasionally 2) slender stems up to 6 dm (2 ft) high. The sap is milky. The erec
. Botanical and vegetation survey of Carter County, Montana, Bureau of Land Management-administered lands . Botany; Rare plants. Asclepias ovalifolia Decaisne O VALLE AF MILKWEED Milkweed Family (Asclepiadaceae) CONSERVATION STATUS U. S. Fish and Wildlife Service: None Bureau of Land Management: Watch. Montana Natural Heritage Program: G5? S1; Demonstrably secure globally, but may be critically imperiled in Montana where it is extremely rare. DESCRIPTION: Ovalleaf milkweed is a rhizomatous perennial with solitary (occasionally 2) slender stems up to 6 dm (2 ft) high. The sap is milky. The erect to spreading, opposite leaves have petioles up to 1 cm long and broadly lance-shaped to elliptic blades, 4-8 cm (1 -3 in) long, with entire margins. Leaves are moderately long-hairy beneath. 1 -3 umbrella-shaped, stalked clusters of 8-20 flowers arise fi-om the axils of upper leaves. Each greenish-white to yellow flower is 8-10 mm high and sessile or on a hairy pedicel up to 20 mm long. Flowers have 5 reflexed corolla lobes, 5-6 mm long, and 5 erect hoods, 4-5 mm long, that are rounded at the tip and surround a greenish or yellowish central column. Each hood has a conical horn inside. The erect spindle-shaped fruits are 6-8 cm (2-3 in) long and ca. 1 cm wide. Each fruit has numerous seeds, each with a light brown tuft of hairs, 18-35 mm long. Flowering in late June-early July. Green milkweed {Asclepias viridiflora) and showy milkweed {A. speciosa) also have broad leaves, but the former lacks horns within the hoods, and the latter has pink to purple flowers. GEOGRAPHICAL DISTRIBUTION Global distribution: Northern Great Plains and Midwest, from fllinois and Manitoba west to eastern Alberta and eastern Wyoming (Great Plains Flora Association 1986). Montana distribution: Carter County. Carter County distribution: The species was first discovered in Montana in 1994 (Heidel and Dueholm 1995; Heidel 1996) at the south- western end of Long Pines unit of the Custer National Forest. Th
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