Reprinted with permission from the New Britten 

 and Brown Illustrated Flora of the Northeastern 

 United States and Adjacent Canada, Vol. 3, page 8( 

 Copyright 1952, The New York Botanical Garden. 



ASCLEPIAS STENOPHYLLA 

 NARROWLEAF MILKWEED 



Narrow leaf Milkweed is a perennial herb with few, erect and usually unbranched stems that are decumbent or upright, 2 

 8 dm high and arise from a thick, woody root. The alternate or opposite leaves are 8-18 cm long, but only 1-5 mm wide. 

 Foliage is moderately to sparsely hairy, and the sap is milky. Umbrella-shaped clusters of 10-25 flowers are nearly 

 stemless in the leaf axils on the upper half of the stem. Each greenish-white to yellow flower is only 7-9 mm long and 

 is borne on a hairy stalk that can be up to 1 cm long. Flowers have 5 reflexed corolla lobes which are ca. 5 mm long, 

 and 5 erect hoods that are distinctly 3-lobed at the tip and which surround a central column. Erect spindle-shaped fruits 

 are 9-12 cm long and less than 1 cm wide. Each fruit has numerous seeds, each with a white tail that is ca. 3 cm long. 



Flowering in June-early July. 



It resembles narrow-leaved forms of ASCLEPIAS VIRIDIFLORA but has flowers with horns. Both ASCLEPIAS 

 PUMILA and A. VERTICILLATA also have narrow leaves, but often filiform and less than 1.5 mm wide. A hand lens 

 reveals the three-lobed hoods of A. STENOPHYLLA that are diagnostic. 



