36 Underwood : The genus Stenochlaena 



review the entire genus. During the past summer, while visiting 



Kew 



imens representing this genus were examined comparatively and 

 the following revision is the result of this first synoptical study of 

 a genus based on the materials of all the great fern collections of 

 the world. How different the result appears from that based on 

 the study of the material at a single center may be seen by com- 

 paring the present revision with the treatment of the same group 

 in Synopsis Filicum, where most of the species of other authors 

 are ruthlessly reduced to synonymy under Acrosticlinm sorbi folium, 



West 



World 



species here recognized should be added ten or more which repre- 

 sent the American development of the genus and which will be 



given a separate treatment. 



iftsis Fil 



niopsis 



icum ; of these three reappear without change; three are here 

 described as new, and the remainder represent species either un- 

 known to the authors of S 

 duced to synonymy by them. 



The genus Stenochlae?ia forms a rather natural group of non- 

 indusiate ferns whose nearest relatives are to be found in the 

 dimorphous species of Stegania R.Br. {Lomaria Willd.) as sug- 

 gested in the name {Lomariopsis) given to one section of the genus 

 when monographed by Fee sixty years ago. In fact the species 

 with narrow pinnae in the sporophyls have often been described in 

 the genus Lomaria, as those with wider pinnae were supposed to 

 have a corresponding relation to Acrostichum. At least four 

 genera have been established from among the species, the name 

 Stenochlaena being the oldest for any member of the group. In 

 recent papers Dr. Christ still maintains the genera Lomariopsis 

 and Stenochlaena as distinct, but this seems less rational than to 

 unite them as sections of one genus. It is true that we have two 

 types of venation represented in the group : the first with the lat- 

 eral veins springing from the midrib, and the second with acces- 

 sory veins parallel and adjacent to the midrib with the lateral 

 veins springing from them. Pinnae jointed to the rachis occur in 

 species with both types of venation. The species with the second 

 type have spiny leaves, while those with the first type have a nor- 

 mally cartilaginous margin to the pinnae. With these slight dif- 



