C72 ASCLEPIADACEAE 



Corolla purple; hoods without teeth; peduncles longer than the 

 pedicels. 

 Hoods not auricled or f;ib))ous at the base; leaves permanently 



tomentose, at least beneath. 9. A. curvipes. 



Hoods with two gibbosities at the base; leaves puberulent 

 when young, glabrous in age. 10. A. Hallii. 



Leaves linear-lanceolate; hoods truncate, Uttle if at all longer than the 

 anthers. 

 Column short; leaves pale. 



Plant more or less tomentose or puberulent, at least when young. 

 Hoods shorter than the anthers; corolla purple; leaves in 

 age glabrate or nearly so. 

 Hoods about half as long as the anthers; umbeLs pedimcled. 



11. A. brachystephana. 

 Hoods only slightly shorter than the anthers; limbel sub- 

 sessile. 12. A. uncinalis. 

 Hoods longer than the anthers; corolla purplish outside, 

 green within; leaves permanently tomentose. 



13. A. macrosperma. 

 Plant glabrous; corolla greenish white; hoods wliite. 



14. A. labriformis. 

 Column more than half as long as the anthers; corolla purple. 



15. A. incarnata. 

 Leaves narrowly linear, verticillate or scattered. 



Corolla usually ash-colored; leaves 4-S mm. wide. 16. A. mexicana. 



Corolla greenish and white; leaves 1-3 mm. wide. 



Plant tall, 4-6 dm. high, from a rootstock; leaves verticillate. 



Hoods entire. 17. A. rcrticillata. 



Hoods dorsally hastate-sagittate. 18. A. galinidcs. 



Plant low, 1-2 dm. high, bushy, from a ligneous base; leaves scattered, crowded. 



19. A. pumila. 



1. A. tuberosa L. Stem 3-6 dm. high, coarsely hirsute, very leafy; leaves 

 usually alternate, short-petioled or subsessile, lance-linear or lance-oblong, sub- 

 cordate to acute at the base, 5-10 cm. long, with revolute margins; corolla-lobes 

 linear-oblong, obtuse, 6-8 mm. long, greenish or reddish orange; column about 1 

 mm. long; hoods linear-oblong or linear-lanceolate, bright orange or yellow, 5-6 

 mm. long; follicles 7-10 cm. long, minutely pubescent. Dry fields and meadows: 

 Ont.—Fla.— Tex.— Ariz.— Minn. Plain. Je-S. 



2. A. syriaca L. Stem 5-15 dm. high, canescent or in age glabrate; leaf- 

 blades elliptic to lance-oblong, 1-1.5 dm. long, 4-11 cm. wide, rounded, truncate 

 or acute at the base, obtuse or mucronate at the apex, green and glabrous or 

 nearly so above, tomentulose beneath; corolla-lobes dull greenish purjjle, 8 mm. 

 long, more or less pubescent; column less than 1 mm. long; hoods whitish or 

 greenish purple; follicles 7-9 cm. long, lance-ovate, tomentose. A. Cornuti Dec. 

 Fields and waste places: N.B. — Ga. — Kans. — Sask. Plain. Je-S. 



3. A. speciosa Torr. Stem tall, 1-2 m. high, finely canescent-tomentose ; 

 leaves oval, subcordate at the base, thick; corolla greenish ])urple; lobes oblong 

 or ovate-oblong, 9-13 mm. long; column short or none; hoods lanceolate, 11-15 

 mm. long, with two blunt teeth below; follicles 7-10 cm. long, with numerous 

 processes. Valleys: Sask. — Minn. — Kans. — Calif. — B.C. Plain — Submont. 

 My-Jl. 



4. A. cryptoceras S. Wats. Stems several from a woody thick root, de- 

 cumbent, 1-2 dm. high, glabrous; leaves very short-petioled or subsessile; blades 

 ovate-orbicular, 4-6 cm. long, glabrous and glaucous, strongly veined, subcordate 

 at the base; corolla-lobes greenish yellow, ovate, acute, about 1 cm. long; column 

 none; hoods flesh-colored, saccate-ovate, about 7 mm. long, rounded on the sides; 

 foUicles ovate. Sandy plains, rocky hills, and clay benches: Wyo. — Colo. — 

 CaUf. — Ore. Plain — Submont. My-Je. 



5. A. latifolia (Torr.) Raf. Stem simple, stout, 3-8 dm. high, minutely 

 puberulent when young; leaves sessile or short-petioled; blades rounded-oval, 

 mucronate and often emarginate at the apex, cordate or subcordate at the base, 

 7-15 cm. long, minutely puberulent; corolla-lobes ovate, 7-10 mm. long, greenish; 

 column thick, very short; hood truncate; follicles ovoid, 6 cm. long, glabrate. 

 A. Jamesii Torr. Dry plains: Neb. — Tex. — Ariz. — Utah. Plain. Jl-Au. 



6. A. arenaria Torr. Stem decumbent or ascending, tomentose, 3-6 dm. 

 long; leaf -blades rectangular-oval or obovate, truncate or retuse and often muc- 



