standley: tidestromia, a new generic name 69 



BOTANY. — Tidestromia, a new generic name. Paul C. Stand- 

 ley, U. S. National Museum. 1 



The three species of Amaranthaceae, tribe Gomphreneae, 

 generally known under the name Cladothrix form a very natural 

 and well defined genus. All are natives of the more arid regions 

 of the western and southwestern United States and northern 

 Mexico, two of them being rather local in their distribution, 

 the third, however, ranging from Kansas and Utah to Texas 

 and to Zacatecas and Sinaloa in Mexico. All three are much 

 alike in general appearance, but they differ constantly among 

 themselves in details of floral structure. The genus is distin- 

 guished from all the other genera of the Gomphreneae by hav- 

 ing the flowers merely glomerate rather than regularly capitate 

 or spicate. Moreover, the leaves subtending the inflorescence 

 become indurate and more or less connate in age, so as to form 

 a sort of involucre. 



The oldest and best known species was published by Nuttall 

 in 1820 as Achyranthes lanuginosa. In 1849 it was transferred 

 by Moquin to Alternanthera. Watson in 1880 established the 

 genus Cladothrix, including not only this species but another de- 

 scribed by Torrey in 1859 as Alternanthera suffruticosa. The 

 first appearance of the generic name Cladothrix in literature is 

 in 1849, when Moquin cites a manuscript or herbarium name of 

 Nuttall, Cladothrix lanuginosa, as a synonym of his own Alter- 

 nanthera lanuginosa. The mere citation of the generic name in 

 synonymy would not, of course, give it any standing under either 

 of the codes of nomenclature now followed by most botanists 

 and Cladothrix when used in this connection must, consequently, 

 date from 1880. Unfortunately for the maintainance of this 

 name in the Amaranthaceae a genus Cladothrix of the Schizomy- 

 cetes had been proposed by Cohn in 1875. Cohn's genus is 

 properly published and is generally accepted by mycologists. 

 It is evident, therefore, that the name Cladothrix can not be main- 

 tained in the Amaranthaceae and that another must be sub- 

 st tuted for it. Since none is available, the writer proposes the 



1 Published by permission of the Secretary of the Smithsonian Institution. 



