942 ASCLEPIADACEAE 
Leaf-blades typically oval: umbels globose: pedicels 2 cm. long. 11. A. variegata. 
Leaf-blades mainly elliptic or elliptic-lanceolate, tapering to each 
end: pedicels drooping, 5 em. long. 12. A. exaltata. 
b. Leaf-blades ovate-lanceolate to linear, glabrous; primary veins ascend- 
ing, never conspicuously transverse, (see also A. exaltata). 
Leaf-blades ovate-lanceolate or long-lanceolate, long-acuminate: co- 
rolla purple-red. ) 13. A. rubra. 
Leaf-blades lanceolate to oblong-linear, short-petioled: corolla pur- 
plish : hoods orange, exceeding the anthers. 14. A. lanceolata. 
Follicles erect on erect fruiting pedicels: primary veins of the leaf-blades 
never transversely ascending. 
Leaf-blades broad, ovate to ovate-lanceolate, oblong-lanceolate or sometimes 
Janceolate. 
Some of the leaves whorled in 4's or 6's: flowers rose-pink. 15. A. quadrifolia. 
Leaves all opposite. : 
Corolla and hoods rose-colored or rarely white. 
Plants glabrous throughout or nearly so: leaves oblong-lanceolate, 
in the variety elongated-linear. 16. A. incarnata. 
Plants hirsute-pubescent: leaves broader. 17. A. pulchra. 
Corolla red-purple: hoods bright orange: leaves oblong to oblong-lan- : 
ceolate. 18. A. Curassavica. 
Corolla and hoods white, tinged with greenor pink: flowers very small. 
Leaf-blades oblong-lanceolate or lanceolate, tapering at each end, ; 
glabrous: seed destitute of coma. 19. A. perennis. 
Leaf-blades oval-oblong, broad at the petioled base. 20. A. Texana. 
Leaf-blades linear or filiform : flowers very small, white or greenish tinged. 
Hoods each terminating in a horizontal or erect lobe: horns exserted. 
Crown slender-stalked, the stalk less than 1 mm. thick: horn exceed- 
ing the hood. 
Leaf-blades filiform or linear-filiform. Ay 
Stems typically solitary : leaves numerous, but not crowded. 91. A. verticillata. 
Stems tufted : leaves contiguous or approximate, very numerous ; 
and crowded. 22. A. pumila. 
Leaf-blades linear. 23. A. linearis. 
Crown short-stalked, the stalk over 1 mm. thick: horn not exceeding 
the hood. 
Umbel typically solitary, sessile: leaves many times longer than 2 5 
the internodes. 24. A. Michauxii. 
Umbels several, peduncled: leaves shorter than the internodes or E 
less than twice their length. 25. A. viridula. 
Hoods notched or emarginate: horn included. 26. A. cinerea. 
B. Hoods erect, dilated above the anthers into a lobed or erose open or closed 
lamina: anther-wings entire or notched at the middleor corniculate at the base. 
Leaf-blades with ascending veins: umbels all lateral. a : 
Hoods 5 mm. high: horn single, arising from the apex of the hood. 27. A. Emoryi. 
Hoods 8 mm. high, very slender at the stalked base: horn with an acute i ME 
dorsal accessory process. 28. A. Lindheimert. 
Leaf-blades with transversely spreading veins: horn arising from the base of 
the hood, exserted over the anthers. 29. A. obovata. 
1. Asclepias decümbens L. Stems decumbent, 3-6 dm. long, hispid or hirsute- 
pubescent, the ends ascending or erect: leaves various, the lower commonly alternate, the 
upper opposite and often notably smaller ; blades oblong, obtuse at the apex, mostly nar- 
rowed and often inequilateral and sometimes hastate at the base, usually revolute on the 
margins, 3-19 em. long: umbels several or numerous, many-flowered, racemose along the 
branches, one usually in each of the upper axils, on peduncles 1-3 cm. long: pedicels 
slender, somewhat pubescent, 1.5-3 cm. long: corolla lobes narrowly oblong, acutish, dark 
or oe orange color, 7 mm. long : column distinct : hoods erect, linear, oblong, orange 
ellow, slightly longer than the subulate inflexed horn, the ventral margins entire or barely 
obed at the base : follicles 10-14 cm. long, slender-fusiform, hipsid-pubescent : seeds 7 mm. 
long, glabrous, marked by fine broken diverging ridges : coma long and abundant. 
In dry fields, New York, Ohio and Illinois to North Carolina and Florida. Occurring also probably 
elsewhere further north. Summer. BUTTERFLY WEED. PLEURISY-ROOT. 
2. Asclepias tuberdsa L. Stems solitary or several, hirsute or rough hirsute-pubes- 
cent, commonly erect or ascending, 3-6 dm. high or more, simple or branched near the sum 
mit, very leafy, the milky sap scanty : leaves usually all alternate ; blades lanceolate-oblong, 
sometimes lanceolate-linear, acute or more rarely obtuse at the apex, 3-9 dm. long, Men 
margins narrowly revolute: umbels cymose at the ends of the stems or branches, or on 7. : 
plants sometimes racemose, many-flowered : pedicels pubescent, 1-1.5 cm. long: coro ii 
lobes narrowly oblong, obtuse, 6-8 mm. long, greenish or reddish orange : column distinc ; 
hoods erect, linear-oblong or linear-lanceolate, bright orange-color or rarely yellow, con 
siderably exceeding the anthers and slightly longer than the filiform exserted incurve 
horn, the ventral margins entire or barely lobed and overlapping at the base : Grider 
salient at the entire base : follicles 7-10 em. long, minutely pubescent : seeds 7 mm. ong, 
glabrous, marked with fine diverging broken ridges: coma long and abundant. 
In dry fields, Maine to Ontario, Minnesota, Colorado, Florida, Texas and Arizona. Summ 
fall. BUTTERFLY WEED. PLEURISY-ROOT. 
er &nd 
