CONTRIBUTIONS FROM THE GRAY HERBARIUM OF 
HARVARD UNIVERSITY. 
New Sertes.— No. LL 
TAXONOMIC AND GEOGRAPHIC STUDIES IN NORTH 
RICAN FERNS. 
Freperic K. Butters. 
(Plate 123.) 
INTRODUCTION. 
Writine about the ferns of China, Christ says, “It has been be- 
lieved and is still believed, that the distribution of ferns differs essen- 
tially from that of Phanerogams, in that the former have more extended 
ranges, and that endemism among them is less marked. Nothing is 
more incorrect. In specialization of species and endemism, the class 
of Pteridophytes is on a level with the remainder of the flora. Wher- 
ever the flora has an original character, and endemic forms play a 
great part, wherever types vary, and give rise to a circle of derived 
forms, these peculiarities appear strongly also among the ferns.” * 
ae no - y Br) 2 a ers Be: | re 

Phanérogams dans ce sens 1 iéres auraient des aires plus vaste, et que l’endémisme 
ntué, Rien n’est plas inexact. La.spécialisation des espéces et endémisme 
pra i Ps tas des Ptéridophytes, vont de pair avec le reste de la flore. Partout ov la flore a 
un caractixe original et ot les formes endémiques jouent un frend Ete, portont ou les types 
tourent d’un cercle de formes dérivées t tout aussi 
bien sur vee Fougéres. Celienicinn. pe Fougires de la Chine au Muséum 
lle de Paris. Bull. Soc. Bot. de France, lii. Mém. i. 9 (1905). 



