ASCLEPIADACEAE. 



[Vol. III. 



14. Asclepias quadrifolia Jacq. 

 Four-leaved Milkweed. (Fig. 2913.) 



A. quadrifolia Jacq. Obs. Part 2, 8. pi. 33. 1767. 



Stem slender, simple, i°-2° high, usually leaf- 

 less below. Leaves thin, sparingly pubescent 

 on the veins beneath, ovate to lanceolate, 2'-6' 

 lo"g. '4 '-2 '2' wide, acute or acuminate, nar- 

 rowed or rounded at the base, or the lowest pair 

 much smaller, obovate and obtuse, the upper 

 and lower opposite, the middle ones usually 

 verticillate in 4's; umbels 1-4, terminal, or 

 rarely in the upper axils; peduncles slender, 

 Yi'-'zYi' long; pedicels about i' long; corolla 

 pink or nearly white, its lobes lanceolate-ob- 

 long, 2"-3" long; column short; hoods white, 

 obtuse at the apex, broadly 2-toothed above the 

 base, twice as long as the anthers and the 

 incurved horn; follicles erect on the erect fruit- 

 ing pedicels, 3'-5' long, glabrous. 



Woods and thickets, Maine and Ontario to Min- 

 nesota, North Carolina and Arkansas. ilay-July. 



15. Asclepias Syriaca L. Common 

 Milkweed. Silkweed. (Fig. 2914.) 



Asclepias Syriaca L. Sp. PI. 214. 1753. 



Asclepias Cornuli Dec. in DC. Prodr. 8: 564. 1S44. 



Stem stout, usually simple, 3°-5° high, finely 

 pubescent at least above. Leaves oblong, oval or 

 ovate, densely pubescent beneath, soon glabrous 

 above, acute or obtuse and cuspidate at the apex, 

 obtuse, narrowed or subcordate at the base, 4'-9' 

 long, 2'-4'2'' wide, the primary nerves wide- 

 spreading; petioles stout, 3"-S" long; umbels 

 several or numerous; peduncles pubescent or 

 tomentose, i/i'-i/i' long; pedicels i'-2' long; 

 corolla green-purple, its segments oblong-lanceo- 

 late, 3"-4" long; column short and thick, the 

 hoods ovate-lanceolate with a tooth on each side, 

 longer than the anthers and the incurved horn; 

 follicles 3'-5' long, erect on recurved pedicels, 

 tomentose and covered with short soft processes. 



In fields and waste places. New Brunswick to the 

 Northwest Territory, south to North Carolina and 

 Kansas. Leaves rarely lanceolate. June-.\ug. 



16. Asclepias speciosa Torr. Showy 

 Milkweed. (Fig. 2915.) 



Asclepias speciosa Torr. .\nn. Lye. N. Y. 2: 21S. 1S26. 

 A. Douglasii Hook. Fl. Bor. Aiii. 2: 53. pi. 132. 1834. 



White-tomentose or cancscent all over, or gla- 

 brate below, pale; stem simple, stout, l°-2>^° 

 high. Leaves thick, broadly ovate or oval, obtuse 

 and cuspidate or acute at the apex, subcordate, 

 rounded or narrowed at the base, petioled, 3'-S' 

 long, 2'-4' wide; peduncles i'-3' long; umbels 

 several or rarely solitary, manj'-flowered; pedicels 

 stout, 9"-:S" long; corolla purple-green, its seg- 

 ments oblong or ovate-oblong, 4"-6" long, tomen- 

 tose on the outer face; column verj- short or none; 

 hoods lanceolate, $"-'" long, obtusish, expanded 

 and with 2 blunt teeth below, the apex ligulate, 

 5-7 times as long as the anthers; horn short, in- 

 flexed; follicles erect or spreading on the recur\-ed 

 fruiting pedicels, 3'-4' long, densely woolly 

 and covered with soft spiuose processes. 



In moist soil, Minnesota to British Columbia, south 

 to Kansas, Utali and California. May-July. 



