GENERA AND SPECIES. Al 
PLATE Vt. 
PTERIS. Linnzus. 
GEN. CHAR.—Fruit-dots on the margins of the frond in a continu- 
ous line, the reflexed margin forming the indusium; sporangia at- 
tached to a vein-like receptacle which connects the tips of the veins ; 
stipes light colored. . 
This is the typical genus of the tribe Pteridez, and is 
- widely distributed. It is characterized by its having the 
spore-cases arranged in a continuous line along the mar- 
gins of the pinnules. The organs of fructification are coy- 
ered by the reflexed margin of the leaflet, which forms a 
continuous membranaceous indusium. 
The various species of this fern differ very widely from 
each other in form and color; some have the pinnules 
very long and linear, like ribbon-grass; others are beauti- 
fully tinted, resembling variegated leaves. 
An examination of the underside of the leaf, with its 
reflexed margin, will always enable the student to deter- 
mine the true character of this genus. It is closely allied 
to the genus Pellzea, which, in fact, was formerly included 
in it. There would seem, however, to be good ground for 
the distinction, and the best authorities have sanctioned 
the separation. Figure 1, pinnules slightly magnified; 
figures 2 and 3, sporangia and spores greatly magnified. 
(Hooker and Bauer); figure 4, reflexed margin laid open, 
showing the venation. 
