102 GENTIAN ORDER 



b. Hoods entire at tip ; leaves ovate to lance- 

 linear A. viridiflora 



Asclepias Linne 1753 Milkweed 



(Named for Asklepios, the Greek god of medicine) 



PL 17, fig. 6-10. 



Sepals 5, united, petals 5, greenish-white to pink or purple, united, 

 turned back, crown-column generally present, crown of 5 concave erect 

 or spreading hoods, each bearing within a slender or awl-shaped incurved 

 horn, stamens 5, pollen-masses solitary in each sac, hanging, stigma nearly 

 flat, 5-angled or 5-lobed, follicles usually thick, taper-pointed ; flowers in 

 terminal or axillary umbels ; leaves opposite, whorled or rarely alternate, 

 entire ; perennial. 



1. Leaves opposite or mostly so 



a. Leaves linear, 5-10 mm. wide A. br achy Stephana 



b. Leaves broader, lanceolate to round 



(1) Flowers red; leaves lanceolate, 1.5-4 cm. 



wide A. incarndta 



(2) Flowers greenish, white, yellowish or 



purplish ; leaves lance-ovate to round 



(a) Leaves lance-ovate, usually velvety- 



hairy, rather acute A. Hdllii 



(b) Leaves broadly ovate to round 

 x. Leaves smooth when mature 



(x) Petals 1-1.5 cm. long; horns con- 

 cealed in hoods A. crypt 6c eras 



(y) Petals 5-7 mm. long; horns ex- 



serted A. Jatifolia 



y. Leaves velvety-hairy 



(x) Hoods long-pointed, 10-15 mm. 



long; leaves pointed A.speciosa 



(y) Hoods blunt, 4-5 mm. long; leaves 



retuse A. arendria 



2. Leaves alternate or scattered 



a. Flowers orange ; leaves lanceolate to oblong, 



hairy A. tuberosa 



b. Flowers greenish-white ; leaves long linear, 



smooth 



(1) Plants 2-8 in. high ; leaves densely crowded A. pumila 



(2) Plants 1-2 ft. high; leaves in whorls 



