MONOPETALOUS EXOGENOUS PLANTS. 447 



SYNOPSIS. 



Tribe. Asclepiadeae. PoUen-msisses 10, fixed by 

 .irs to the cleft processes of the flat or conical stigma, 



nrl nlniia 



pairs 

 pendulous 



* Stamineal crown single, h-leaved. 



t Lobes of the corolla reflexed or spreading. 



Leaves qf the crown inclosing a horn-like appendage Asclepias. 



without appendages Acebatbs. 



ASCLEPIAS, L. Milkweed; Silkweed. 



Calyx 5-parfced; corolla wheel-shaped, deeply 5-parted, 

 reflexed; croiuii composed of 5 hooded leaves, each con- 

 taining an incurved horn-like appendage ; ;?o?/e?i-masses 10, 

 by pairs, each pair occupying the contiguous cells of adja- 

 cent anthers, and suspended by a slender stalk from the 

 projecting angles of the stigma; follicle many-seeded; 

 seeds obovate, flat, usually comose. — Perennial herbs, with 

 mostly siftple (not twining) stems, and opposite alternate 

 or whorled leaves ; floiuers in lateral (between the leaves) 

 and terminal umbels. 



% stems herbaceous ; seeds comose, 

 * Follicles spiny ; leaves opposite. 



A. coRNUTi, Decaisne. Softly pubescent; stem stout, 

 erect, obscurely 4-angled ; leaves oval-oblong, short-petioled, 

 mucrotena, soon smooth above, the lowest somewhat cor- 

 date; umbels numerous, many-flowered, long-peduncled; 

 corolla greenish pnrple, one-fourth as long as the pedicels; 

 leaves of the crown pale purple, ovate, obtuse, longer than 

 the incurved horn ; follicle ovate-oblong, woolly, armed 

 with soft spines. Stem 3°-4° high, sometimes branched ; 

 leaves 4-8' long ; pedicels I'^IJ' long, purplish ; corolla 

 ^' wide. 



