Vol. XXIV, pp. 243-250 December 23, 1911 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



THE AMERICAN SPECIES OF FAGONIA. 



The representatives of the genus Fagonia are confined chiefly 

 to two parts of the earth, the more arid regions bordering the 

 Mediterranean in Europe, Asia, and Africa, and the deserts 

 aboufthe Gulf of California in North America. Two species 

 occur on the western coast of South America in Chile and Peru, 

 while another has only recently been described from the interior 

 of Mexico. The genus is composed of remarkably uniform 

 species that are similar in general appearance and differ only 

 in minor characters such as pubescence, shape of leaflets, and 

 form of stipules. In the Kew Index but two names are recog- 

 nized as valid. All the Old World species, of which a consid- 

 erable number have been described, alongwith Fagonia chilensis 

 and F. californica, are referred to the type species, F. cretica L. 

 After an inspection of the Old World material in the National 

 Herbarium, consisting of many more sheets than there are of 

 American collections, the writer is inclined to believe that there 

 are several species in the Eastern Hemisphere although possibly 

 not so many as in America. Our American forms certainly are 

 more diversified than those of Europe and Africa. The latter, 

 for example, exhibit no such distinct types as Fagonia califor- 

 nica, F. palmeri, and F. scoparia. 



The genus is ably treated by Dr. P. A. Rydberg in the part 

 of the North American Flora dealing with the Zygophyllaceae, 

 five species being recognized for North America. Before the 

 publication of that monograph only two species had been de- 

 scribed from the region, F. californica and F. palmeri. Miss 

 A. M. Vail in 1895 named a subspecies of Fagonia californica 

 from the Southwest. 



■IS— Proc. Biol. Soc. Wash., Vol. XXIV, 1911. (243) 







A 



BY PAUL ('. STANDLEY. 



[By permission of the Secretary of the Smithsonian Institution.] 



