Asclepias ovalifolia Decaisne 



OVALLEAF MILKWEED 



Milkweed Family (Asclepiadaceae) 



CONSERVATION STATUS 



U. S. Fish and Wildlife Service: None 



Bureau of Land Management: Watch. 



Montana Natural Heritage Program: G5? SI; 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 finit 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 Illinois 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. This is the only place it has been 

 reported in the state. 



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