182 



FOUNDATIONS OF BOTANY 



greenish ; hoods white, with 2 teetli ; horns with an awl-shaped 

 point extending far out of the hoods. Damp thickets N. and E. 



4. A. variegata, L. White Milkweed. Stem stout, leafless 

 and smooth below, leafy and downy in lines above. Leaves oppo- 

 site, the middle ones sometimes in fours, petioled, ovate to obovate. 



Fig. 20. — Flower of Asclepias Cornuti. 



A, entire flower ; B, vertical section ; C, diagram ; D, details of pollen-masses 

 and glands, ca, calyx ; c, corolla ; lid, hood ; hn, horn ; a, anther ; s, stig- 

 ma ; o, ovary ; g, gland ; p, pollen-mass. (All considerably enlarged.) 



cuspidate, smooth on both sides, iDale beneath, edges slightly crenate. 

 Umbels 1-5, compact, downy, 1-2 in. long ; pedicels erect, as long, 

 as the peduncles. Corolla white, often purple at the base ; hoods 

 roundish, spreading, a little longer than the thick, awl-pointed, 

 incurved horn. Dry, open woods E. and S.* 



5. A. quadrifolia, L. Four-leaved ^Iilkweed. Stem slender, 

 1^-2 ft. or more high, usually leafless below. Leaves in 1 or 2 



