CHARACTERS OF TRIBES AND GENERA. 103 
Ozs.—This genus is distinguished from Pleopeltis prin- 
cipally by the venules being more compoundly anastomose, 
the fronds being smooth, and the sori destitute of induse- 
form scales. It comprehends a considerable number of 
species, all, with two or three doubtful exceptions, natives 
of the tropical and sub-tropical regions of the Eastern 
hemisphere. 
P. pustulata (Forst.) (v v.) ; P. Billardieri (E. Br.) (vv); 
. P. vulgare, Pr. Ceci: P. longipes, J. Sm. (v v.); P. pel- 
tidea (Link.) (v v.); P. terminales (Link) (v eis P. 
glauca, J. Sm. (v v.) ; P. nigrescens (Bl) (v v.) ; (P. saccata, 
J. Sm., 1857); P. longissima, Bl. (v v.); P. Schom- 
burghiana, J. Sm. Lond. Jour. Bot. i. p. 196 (Polypodium 
Schomburgiana, Kze. in Schk. Supp. Fil. t. 42). 
Oss.— This is a native of British Guiana, and is peculiar 
in being an example of Phymatodes, thus showing that the 
genus is not entirely restricted to the Eastern hemisphere. | 
It, however, may be called an aberrant species; it has a 
remarkable caudex, from half an inch to an inch in 
thickness, densely covered with long lanceolate, acumi- 
nate, silky scales, very much resembling the well-known 
Hare’s-foot Fern, Davallia canariensis ; the fronds are distant, 
short, stipate, oblong, elliptical, 1 to 1i feet in length, and 
2 to 3 inches in width, smooth, coriaceous, with thickened 
margin; the sori are large, round, or oblique oblong, 
forming a medial row on each side of the mid-rib. The 
peculiarity of this Fern has led Klotzsch to place it under 
. a distinct genus, which he names Mecosorus. Another 
` remarkable American species is Polypodium (Phymatodes) 
‘bifrons, Hook. “Species Filicum,” and Hook. Fil. Exot., 
t.59. The character of the candex is described as being 
long, slender, naked; the sterile fronds being elliptical, — 
3 to 4 inches in length, the fertile narrow, linear, 5 to 6 — — 
