THE GYMNOGRAM. 107 
and so near together as to become laterally confluent into a broad 
horse-shoe-shaped band, forms the genus Pterozoniwm, which may 
be considered distinct. 
The characteristic feature of Gymnogramma is the forking of the 
linear sometimes much elongated sori, which forking, though not 
occurring in the case of every sorus, does occur more or less fre- 
quently over every frond. The spore-cases are ranged in lines 
along the back of the veins, sometimes in a very scattered manner, 
sometimes more crowded, and these lines of spore-cases being con- 
tinued downwards more or less frequently past the point where the 
veins branch, become like them forked, which is the leading charac- 
teristic of the genus. A linear dorsal naked sorus, constantly simple, 
¿. e. without this forking, indicates the genus Grammitis, which is 
closely allied to Gymnogramma. : 
Our native Channel Island species, Gymnogramma leptophylla, 
belongs to the § Plewrosorus, characterised by having short or 
shortish lines of spore-cases, the fronds being smooth or hairy. 
This group contains another annual species, from the West Indies, 
Gymnogramma cherophylla, as well as several others not annual, 
of a different aspect. The remaining sections are :—§ Ceropteris, in 
which the sori are much as in the § Pleurosorus, but the fronds are 
farinose-ceraceous beneath, as represented by Gymnogramma chryso- 
phylla; § Eriosorus, with sori as in the last, but the fronds lanate 
beneath, as in Gymnogranuna lanata; and $ Neurogramma, the most 
distinct of any, in which the sori form long parallel-forked lines, 
often approximate, and closely placed over all the under surface of 
the fertile parts; this group, moreover, containing some species 
which have smooth and others which have hairy fronds, is repre- 
sented by the South American Gymnogramma tomentosa, and the 
Eastern Gymnogranuna javanica. 
The name is derived from the Greek gymnos, naked, and gramme, 
a line. 
BRITISH SPECIES. 
G. leptophylla a small, fragile, annual, with twice or thrice pinnate fronds. 

