4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 6$ 



Safford (no. 996) . Besides additional material of the type collection 

 there are at hand two further collections : ( 1 ) a small but complete 

 specimen of the Wilkes Exploring Expedition, hitherto unnamed 

 and not mentioned by Brackenridge, labelled merely " Peru," and 

 (2) excellent small specimens collected near Oroya, Peru, altitude 

 3,700 meters, July 14, 1914, by Dr. and Mrs. J. N. Rose (no. 18707). 

 All of these specimens are clearly of one species, despite the extremes 

 of size. 



Cheilanthes omatissima is without much doubt the species illus- 

 trated by Hooker 1 as " Cheilanthes scariosa Presl," and probably 

 represents the species passing under this name in herbaria. It is 

 not, however, the Peruvian plant which Presl had in hand in describ- 

 ing his Cheilanthes scariosa^ which appears to be a form of C. 

 myriophylla. Presl cites as a synonym Acrostichum scariosum 

 Swartz, 1806, founded on a Mexican plant first described as Acros- 

 tichum lanuginosum Willd., 1802 {not A. lanuginosum Desf., 1800) ; 

 but this again is different, being reckoned a Notholaena by Christen- 

 sen under the name N. scariosa (Swartz) Baker. Obviously, then, 

 since the name Cheilanthes scariosa Presl was not originally proposed 

 for a supposed new. species, but was intended as a transfer of the 

 older name Acrostichum scariosum Swartz, it is inadmissible to use 

 it for a second species, as has been done by Christensen. But leaving 

 out of consideration the matter of nomenclature, it will be seen from 

 a careful reading of Presl's description that Hooker's plant is very 

 different from Presl's. The former is almost certainly that here 

 described as C. omatissima; the latter is, in all probability, C. myrio- 

 phylla Desv. 



Cheilanthes omatissima is the most densely and copiously palea- 

 ceous species of Cheilanthes known to the writer, the scales of the 

 under side of the lamina being not only very large but widely over- 

 lapping and extending beyond the edges of the segments to form a 

 thick, solid, unbroken protective covering, entirely concealing the 

 segments. The cellular structure of the scales is very minute ; trie 

 surfaces are finely lineolate, the cells being very narrow and greatly 

 elongate, pointed, and with thin, almost colorless partition walls. 

 This is in marked contrast to C. Incarum, described hereafter. 



The upper surface of the lamina of C. omatissima bears a lax but 

 close covering of long, coarse, silky, white " wool," which upon 

 careful dissection is found to proceed from the under side of the 



1 Sp. Fil. 2 : pi. 104. A. 



