Vol. 31, pp. 139-152 November 29, 1918 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



THE LIP- FERNS OF THE SOUTHWESTERN UNITED 



STATES RELATED TO CHEILANTHES 



MYRIOPHYLLA.* 



BY WILLIAM R. MAXON. 



Under the names Cheilanthes myriophylla Desv., C. Clevelandii 

 D. C. Eaton, and C. Fendleri Hook., but chiefly under the first, 

 there have been associated in herbaria for many years several 

 species whose distinctive characters have been so little observed 

 or correlated that identical material has been variously labelled 

 and the whole complex has been regarded either as hopelessly 

 confused or as representing two or three species of inordinate 

 variation. An extreme view of the situation was given definite 

 expression by D. C. Eaton, who wrote in the Botany of the 

 Death Valley Expedition as follows: 



' I find it impossible to distinguish between C. myriophylla 

 and C. Fendleri. Specimens which I had at one time called 

 C. Fendleri I afterwards referred to C. myriophylla, and Mr. 

 Davenport again placed in C. Fendleri. Even Mr. Faxon's 

 carefully drawn figures in the Ferns of North America 

 (t. lxxix) do not show the differences which I thought I could 

 discern when that book was written, and I am persuaded that 

 C. myriophylla is a fern which represents a multitude of varying 

 forms, connected by all degrees of intermediate conditions, 

 which it is not worth while to try to separate, even into named 

 varieties, "t 



Others, who have been familiar with one or more of the forms 

 in the field and have noted their peculiar characters, have 



* Published with the permission of the Secretary of the Smithsonian Institution. 

 t Contr. U. S. Nat. Herb. 4 : 227. 1893. 



37— Proc, Biol. Soc. Wash., Vol. 31, 1918. (139) 



