666 ASCLEPIADACEAE (MILKWEED FAMILY) 



12. A. variegata L. Stem 3-9 dm. high ; leaves (4-5 pairs) ovate^ ovat^ or 



obovate, somewhat wavy, contracted into short petioles, middle ones sometime? 

 whorled ; pedicels {numerous and crowded) and peduncle short, downy ; divi- 

 sions of the corolla ovate, whits; hoods orbicular, entire, purplish or reddish, 

 the horn semilunar with a horizontal point. — Dry woods, L. I. to Ind., s. to 

 Fla., and w. La. May, June. — Kemarkable for its compact umbels of nearly 

 white flowers. 



1). Leaves mostly pubescent or puberulent ; hoods obtuse^ entire^ twice or thrice 

 the length of the anthers. 



13. A. ovalifblia Dene. Low, 1.5-6 dm. high, soft-downy especially the 

 lower surface of the ovate or lanceolate-oblong acute short-petioled leaves 

 (3.5-8 cm. long); umbels loosely 10-18-flowered, sessile or peduncled ; pedicels 

 slender ; hoods oblong, yellowish, with a small horn, about the length of the 

 oval greenish-white corolla-lobes (tinged with purple outside). — Prairies and 

 oak openings, 111. and Wise, to S. Dak. and Man. June, July. 



4H. 4M. Follicles and pedicels erect; leaves often ivhorled; glabrous or nearly so. 



= Leaves ovate to broadly lanceolate, thin, rather slender-petioled. 



14. A. quadrifblia Jacq. Stem slender, 3-8 dm. high, mostly leafless below, 

 bearing usually 07ie or two whorls of four in the middle and one or two pairs 

 of ovate or ovate-lanceolate taper-pointed petioled leaves (0.5-1 dm. long); pedi- 

 cels slender ; corolla-lobes pale pink, oblong ; hoods white, ^Uiptical-ovate, the 

 incurved horn short and thick. — Dry woods and hills, N. H. to Ont. and Minn., 

 s. to N. C. and Ark. May-July. 



15. A. perennis Walt. Stems 3-7 dm. high, persistent or somewhat woody 

 at the base; leaves lanceolate or lanceolate-ovate, tapering to both ends, thin, 

 rather slender-petioled ; flowers white, small ; the small hoods of the crown 

 shorter than the needle-shaped horn ; seeds sometimes destitute of a coma 1 — 

 Low grounds, Ind. to Mo., Fla., and Tex. May-Aug. 



= = Leaves narrowly linear to filiform; horn subulate^ exserted; column 



conspicuous. 



16. A. verticillata L. Stems slender, simple or sparingly branched, 3-9 dm. 

 high, from a fibrous root, very leafy to the summit ; leaves linear, with revolute 

 margins, 3-6 in a whorl; umbels small, lateral and terminal; divisions of the 

 corolla ovate, greenish-white ; hoods roundish-oval, about half the lengt,h of the 

 incurved claw-shaped horns. — Prairies and open woods, Mass. to Sask., and 

 southw. 



17. A. pumila (Gray) Vail. Similar; loic (1-1.5 dm. high) and many- 

 stemmed from a woody caudex; leaves much crowded, spirally arranged, filiform 

 or filiform-linear. (A verticillata, var. Gray.) — Dry plains, w. la. and Neb. 

 to Col. and N. Mex. 



§ 2. Anther-wings broadly rounded at base and conspicuously auriculate-notched 

 just above it; hoods with a minute horn exserted from the 2-lobed apex. 



18. A. stenophylla Gray. Puberulent, but foliage glabrous ; stems slender, 

 0.3-1 m. high ; leaves narrowly linear, the upper alternate, lower opposite ; 

 umbels several, short-peduncled, 10-15-flowered ; corolla-lobes oblong, greenish ; 

 hoods whitish, equaling the anthers, conduplicate-concave ; follicles erect on 

 ascending pedicels. {Acerates angustifolia Dene.) — Dry prairies, Neb. to Mo., 

 southw. and westw. June- Aug. 



8. ACERAtES Ell. Green Milkweed 



Nearly like Asclepias ; but the hoods destitute of crest or horn (whence the 

 name, from a- privative, and K^pas, a horn). — Flowers greenish, in compaci 

 many-flowered umbels. Leaves opposite or irregularly alternate, short-petioled 

 or sessile. Pollen-masses slender-stalked. Follicles not tuberculate. 



