232 



THE BOOK OF CHOICE FERNS. 



(especially the under -surface) with a farinose powder varying in thickness as 

 well as in de]3th of colour. 



The distinctive characters of the genus reside not only in the naked 

 nature and in the disposition of the sori, which arise from the veins of the 

 under-surface of the fronds, but also in their form, which is linear or linear- 

 oblong, and either simple (undivided) or forked, and in their being irregularly 

 scattered over the entire under-surface of the fronds. They are medial (situated 

 along the veins between the base and the apex), -and usually occupy almost 

 the whole length of the venules (minor veins). After a time they become 

 confluent, and when this occurs the proper distribution and arrangement of 

 the spore masses are no longer apparent. The genus as it is now accepted 

 embraces many plants which formerly were classed under different generic 

 names, as follow : 



Ceropteris (Ce-rop'-ter-is), Lhik. To this section belong the majority 

 of the Ferns popularly known as Grymnogrammes, and which differ from 

 Eugymnogramme only by the fronds being coated with white or yellow 

 powder. 



DiCTYOGRAMME (Dic-ty-og-ram'-mc), Moore. The plants belonging to this 

 section are distinguished by the coriaceous (leathery) texture and prominent 

 veins of their fronds. They are pro^dded mth underground rhizomes (prostrate 

 stems). 



Eugymnogramme (Eu-gym-nog-ram'-me), Desvaux. Species with foliage 

 of various forms, from simple to quadripinnatifid (four times divided nearly to 

 the midrib), are included under this head. They have free veins and their 

 under-surface is not powdery. 



Leptogramme (Lep-tog-ram'-me), /. Smith. A group of Ferns with free 

 veins and elongated sori. 



Selliguea (Sel-h^-gue-a), Bory. The |)lants of this section have fronds 

 of a leathery texture, simple or compound, with main veins mostly prominent 

 and smaller veins variously and copiously anastomosing (intermixed) ; they 

 are also distinct through their elongated sori. 



Syngramme (Syn-gram'-me), /. Smith. The species known by this name 

 are distinct from the plants belonging to the other sections by the veins of 

 their fronds being close, nearly parallel, and united only by transverse veinlets 

 near the margin. 



