MILKWEED FAMILY 183 



Leaves broadly oval or rectangular-oval or nearly orbicular, obtuse or 

 retuse at both ends; umbels sessile. 

 Plant puberulent when young, glabrate in age ; column very short. 



5. A. laiifoHa. 

 Plant tomentulose; column half as long as the anthers. 



6. A. arenaria. 

 Leaves ovate or lanceolate, or rarely oval, acute. 



Leaves ovate or ovate-lanceolate, more or less tomentose, at least when 

 young. 

 Hoods truncate, slightly longer than the anthers; leaves sessile, 



with rounded or subcordate bases. 7. A. erosa. 



Hoods ovate-oblong to lanceolate, much exceeding the stamens; 

 leaves petioled. 

 CoroUa yellowish; hoods with a tooth on each margin, not 

 auricled or gibbous at the base; peduncles shorter than the 

 pedicels. 8. A. ovalifolia. 



Corolla purple; hoods without teeth; pedtmcles longer than the 

 pedicels. 

 Hoods not auricled or gibbous 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, httle if at all longer than the 

 anthers. 

 Ooliunn 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 peduncled. 



11. A. brachystephana. 

 Hoods only slightly shorter than the anthers; umbel 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 white. 



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 a.sh-colored ; leaves 4-8 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. verticillata. 



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



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



19. A. pumila. 



5. ASCLEPIODORA A. Gray. SpiiSer Milkweed. l. A. decumbens. 



Family 107. CONVOLVULACEAE. Mohning-glohy Family. 



styles distinct or ijartly so. 



Corolla not plaited; styles simple. 1. Chess.4.. 



CoroUa plaited; styles 2-cleft. 2. Evolvulus. 

 Styles united up tb the stigmas. 



Stigmas subglobose. 3. Ipomoea, 



Stigmas linear to oblong-cylindric. 4. Convolvulus. 



1. CRESSA L. 



Stem erect; pedicels longer than the leaves. 1. C erecta. 



Stem decumbent; pedicels shorter than the leaves. 2. C. depressa. 



2. EVOLVULUS L. l. E. Nuttallianus. 



3. IPOMOEA L. MOBNING-GLOKY. 



Plant bushy, not climbing; leaves linear. 1. J. leptophylla. 



Plant climbing; leaf-blades cordate. 2. I. purpurea.. 



i. CONVOLVULUS (Tourn.) L. Bindweed, Morning Glory. 



Calyx not closely subtended by the bracts. 



Plant not canescent; leaf-blades hastate, but otherwise entire. 



Whole plant glabrous or nearly so. 1. C. arvensis. 



Stem and lower surface of the leaves with scattered long hairs. 



2. C. ambigens. 

 Plant more or less canescent; leaves usually lobed or dissected. 



Main divisions of the leaf-blades ovate or oblong, obtuse, lobed; sepals auricled 

 at the base. 3. C. hermannioides. 



