108 GENTIANALES 



lobes reflexed. 3. Acerates. 



Climbing vines, corona of flat bodies terminating in 2-cleft awns. 



4. Gonolobus. 



1. Asclepias. 740. 



Leaves not linear, lanceolate to nearly orbicular. 

 Leaves mostly alternate, sap scarcely milky. 1. A. tuberosa. 



Leaves opposite. 



Flowers bright red or purple. 



Flowers large, about 1.5 cm. long, hoods 6 mm. long, leaves 3.5 

 cm. or more wide. 2. A. purpurascens. 



Flowers smaller, hoods, 2-3 mm. long, leaves less than 3.5 mm. 

 wide. 3. A. incarnata. 



Flowers greenish, yellowish, white or merely tinged with purple. 

 Leaves narrowed or acute at the apex. 

 Glabrous or nearly so. 



Corolla segments 10 mm. long or more, hoods longer than 

 the incurved horn. 4. A. sullivantli. 



Corolla segments less than 10 mm. long, hoods much shorter 

 than the incurved horn. 6. A. obtusifolia. 



Canescent or tomentose at least on the lower surface of the 

 leaves. 

 Corolla segments 4-8 mm. long, hoods less than 1 cm. long. 

 Leaves 10-23 cm. long. 7. A. syriaca. 



Leaves 5-8 cm. long. 10. A. ovalifolia. 



Corolla segments 8-12 cm. long, hoods 1 cm. or more long. 



8. A. speciosa. 



Leaves not narrowed but truncate or emarginate at the apex. 



Minutely puberulent or glabrous when old. 5. A. latifolia. 



Densely tomentose-canescent all over. 9. A. arenaria. 



Leaves linear. 



Leaves verticilate, causule glabrous 5-7 cm. long. 11. A. verticillata. 



Leaves scattered, capsule puberulent 3-5 cm. long. 12. A. pumila. 



1. Asclepias tuberosa L. Butterfly Weed, Pleurisy Root. 



On bluffs and prairies in the eastern part of the state. Crete; Dakota 

 County; Douglas County; Fairbury; Lincoln; Wahoo; Wym^ore. 



2. Asclepias purpurascens L. 

 Reported from Weeping Water. 



3. Asclepias incarnata L. i Swamp Milkweed. 

 In meadows and swampy places over most of the state. Cherry 

 County; Haigler; Lancaster County; Long Pine; Mullen; Ponca River; 

 Simeon. 



4. Asclepias suliivantii Engelm. Sullivants Milkweed. 

 In low prairies and meadows in the southeastern portion of the state. 

 Lincoln; Talmage; Weeping Water; Wood River. 



5. Asclepias latifolia (Torr.) Raf. 



In dry places in the southwestern part of the state. Haigler. 



6. Asclepias amplexicaulis J. E. Smith. 

 Asclepias obtusifolia Michx. 



Wooded bluffs and fields in the southwestern part of the state. Weep- 

 ing Water. 



