510 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Pedicels deflexed in fruit; flowers dull purplish or 

 whitish; plants lower, 50 cm. high or less, 

 spreading, much branched near the base. 

 Hoods longer than the anthers; flowers green- 

 ish white - 7. A. involucrata. 



Hoods shorter than the anthers; flowers pur- 

 plish. 

 Hoods about half as long as the anthers; 



umbels pedunculate 8. A. brachystephana. 



Hoods only slightly shorter than the an- 

 thers; umbels subsessile 9. A. uncialis. 



Leaves broadly oblong to orbicular, mostly obtuse or retuse. 



Fruit echinate; leaves acute or acutish 10. A. speciosa. 



Fruit smooth; leaves obtuse or retuse. 



Stems very short, 5 cm. long or less; leaves as 



broad as long or broader 11. A. nummularia. 



Stems 20 cm. long or more; leaves usually much 

 longer than broad. 

 Leaves thin, glabrous, more or less glaucous, 



sessile or clasping 12. A. elata. 



Leaves veiy thick, more or less tomentose, at 

 least when young, never glaucous, 

 short-petiolate. 

 Stems, pedicels, and young leaves densely 



tomentose 13. A. arenaria. 



Stems, pedicels, and leaves sparingly 



tomentose or glabrous 14. A. latifolia. 



1. Asclepias macrotis Torr. U. S. & Mex. Bound. Bot. 164. pi. 45. 1859. 



Type locality: "Rocky hills near El Paso, and on the mountains below San 

 Elceario," Chihuahua. 



Range: Western Texas and southern New Mexico and southward. 



New Mexico: Mangas Springs; Kingston; Organ Mountains; Buchanan; Sandia 

 Mountains. Dry, rocky hills, in the Upper Sonoran Zone. 



2. Asclepias quinquedentata A. Gray, Proc. Amer. Acad. 12: 71. 1876. 

 Asclepias quinquedentata neomexicana Greene, Proc. Amer. Acad. 16: 103. 1880. 

 Type locality: San Pedro River, western Texas. 



Range: Western Texas to Arizona. 



New Mexico: Coolidge; Mogollon Creek; Gilmores Ranch. Transition Zone. 



3. Asclepias pumila (A. Gray) Vail in Britt. & Brown, Illustr. Fl. 3: 12. 1898. 

 Asclepias verticillata pumila A. Gray, Proc. Amer. Acad. 12: 71. 1876. 



Type locality: "The western dry plains from Nebraska to New Mexico." 

 Range: South Dakota and Arkansas to Colorado and New Mexico. 

 New Mexico: Cabra Springs; Nara Visa; Gavilan Creek; Leachs. Plains and low 

 hills, in the Upper Sonoran Zone. 



4. Asclepias galioides H. B. K. Nov. Gen. & Sp. 3: 188. 1818. 



Type locality: "Crescit in temperatis Regni Novae Hispaniae, inter Valladolid 

 do Mechoacan et locum Cuiseo." 



Range: Kansas and Colorado to Arizona, western Texas, and Mexico. 



New Mexico: Cnininon throughout the State. River valleys and wet grounds, in 

 the Lower and Upper Sonoran zones. 



