XXV. AXETIUM. 
45 
sterile fronds, where it is evident it indicates a decisive character, h}' 5vhich the genus maj- he readily 
distinguished — namely, a continuous marginal 
transverse vein, connecting all the oblique veins 
by their apices. Fig. 25 represents a pinna of 
the sterile frond, and a portion of the fertile 
frond of Olfevsia cervina (med. size). 
1, 0. CERVINA, Presl (Acrosticiium, SivaHz ; 
PoLYBOTRYA, Kaulfuss ). — A vcry elegant evergreen 
stove Fern, from the West Indies. Sterile fronds 
glabrous, lanceolate, pinnate, reclining, from two to 
throe feet long; pinnaj oblong- acuminate, coriaceous, 
bright green, rounded at the superior base, the inferior 
truncate. Fertile fronds erect, bipinnate, from two 
to three feet long ; pinnm linear, sporangiferous 
throughout ; stipes covered with long narrow scales. 
The fronds are terminal, adherent to a thick short 
creeping scaly rhizome. 
The fertile frond of this species is usually bipin- 
nate ; when pinnate only, it is the 0. corcovadensis of 
Eaddi. AVe have both forms, gathered at the same 
time from one plant ; they are, consequcntljq merely 
accidental modifications of one species. 
XXV. ANETIUM, SpKtyerher. 
iSjJore-cascs few, irregularly scattered through- 
out the under surface of 
tlie fronds, often collec- 
ted in small groups or 
lines. Venation uniform, 
reticulated, the are- 
oles elongated. Fronds 
simple. Ehkonie creep- 
ing. — Namedcrivedfrom 
anetos, lax; alluding to 
the sori being sparse and 
scattered. 
The habit of this genus 
(which contains hut one 
species;, and its few scattered sporangia, arc the characters by which it is 
separated from Acrosiichum. Fig. 26 represents a frond of Anetium citri- 
fuUuin (med. size). 
1. A. ciTRiFOLiuM, SplUgerher (Acrostichum, ; Antrophyom, Fee ). — A 
dwarf ornamental evergreen stove Fern, from the West Indies. Fronds simple, uni- 
form, glabrous, somewhat membranous, oblong-elliptical, attenuated at the base, six 
to ten inches long ; lateral, articulated with a scaly fibrous creeping rhizome. Sori 
irregularly scattered. 
XXVI. HYMEXODIUM, Fee. 
Sori amorphous, densely C05’ering the under surface of the fertile frond. 
Venation uniform, internal, reticulated, forming large elongated areoles. 
Fronds simjile, one foot or more in length, hairy. Fhhome creeping, and 
densely covered with hair-like scales.— Name derived from hymen, a mem- 
brane ; from the membranaceous texture of some of the species. 
F.ij. 2C. 
