FLOWERING PLANTS AND FERNS OF ARIZONA 545 



from the quadrangular and smooth, or nearly smooth, seeds of E. 

 melanadenia. 



33. Euphorbia gracillima S. Wats., Amer. Acad. Arts and Sci. Proc. 21 : 



438. 1886. 



Chamaesyce gracillima (S. Wats.) Millsp., Field Museum Nat. 

 Hist. Bot. Ser. 2: 409. 1916. 



Tucson Mountains, San Solano, and Sells (Pima County), 2,000 to 

 2,500 feet. Southern Arizona to Sinaloa. 



34. Euphorbia revoluta Engelm. in Torr., U. S. and Mex. Bound. But. 



186. 1859. 



Chamaesyce revoluta Small, Fl. Southeast. U. S. 711, 1333. 1903. 



Coconino, Mohave, Yavapai, Gila, Cochise, Santa Cruz, and Pima 

 Counties, 3,200 to 5,900 feet. Colorado to Arizona and Chihuahua. 



35. Euphorbia arizonica Engelm. in Torr., U. S. and Mex. Bound. 



Bot. 186. 1859. 



Euphorbia versicolor Greene, Bot. Gaz. 6: 184. 1881. 

 Chamaesyce arizonica Arthur, Torreya 11: 260. 1911. 

 Chamaesyce versicolor Norton, Contrib. U. S. Natl. Herbarium 

 25: 345. 1925. 



Grand Canyon (Coconino County), Yucca (Mohave County), 

 and in Greenlee, Graham, Gila, Maricopa, Santa Cruz, Pima, and 

 Yuma Counties, 1,000 to 4,200 feet, type from Arizona (Schott in 

 1856). Texas to southeastern California and northern Mexico. 



36. Euphorbia setiloba Engelm. ex Torr., U. S. Kpt. Expl. Miss. 



Pacif. 5: 364. 1857. 



Chamaesyce setiloba Millsp. in Parish, Cat. PI. Salt on Sink 

 6. 1913. 



Greenlee and Cochise Counties to Mohave and Yuma Counties, 

 1,000 to 5,000 feet. Western Texas to California and northwestern 

 Mexico. 



37. Euphorbia serpyllifolia Pers., Syn. PL 2: 14. 1806. 



Chamaesyce serpyllifolia Small, Fl. Southeast. U. S. 712, 1333. 



1903. 

 Chamaesyce rugulosa (Engelm.) Rvdb., Torre} T Bot. Club Bui. 



33: 145. 1906. 

 Chamaesyce neomexicana (Greene) Standi., Contrib. U. S. 



Natl. Herbarium 13: 199, 227. 1910. 



Apache County to Mohave and Yavapai Counties, southeastward 

 to Cochise and Santa Cruz Counties, 3,000 to 7,200 feet. Widely 

 distributed in western North America, from Alberta to Mexico. 



38. Euphorbia glyptosperma Engelm. in Torr., U. S. and Mex. Bound. 



Bot, 187. 1859. 



Chamaesyce glyptosperma Small, Fl. Southeast. U. S. 712, 

 1333. 1903. 



Apache County to eastern Coconino County (House Rock), 5,000 

 to 7,500 feet. New Brunswick to British Columbia, south to Texas 

 and northeastern Arizona. 



