CHARACTERS OF TRIBES AND GENERA. 3389 
196.—GrzicHENIA, Sm. (1793). 
Hook, Sp. Fil.; Mertensia, Willd. ; Dicranopteris, Bernh. ; 
Sticherus and Calymella, Presl. 
Vernation sarmentose. Fronds long stipate, 1 to 6 or 
more feet high, once or many times dichotomously 
branched, ultimate divisions (pinne) linear lanceolate, 
lacine plain or recurved and saccate, smooth, glaucous, or 
more or less pubescent or squamose. Veins simply or 
pinnately forked, venules free, the lower exterior one fer- 
tile, sporangiferous receptacle, terminal, lateral, or nearly 
axillary superficial, Sporangia 3 to 8, forming punctiform 
naked sori, 
Type. Polypodium dichotomum, Thunb. 
Illust. Hook. and Bauer, t. 39 and 41 A and B; Moore 
Ind. Fil., p. 87, B; J. Sm. Ferns, Brit. and For., f. 136 ; 
Hook. Syn. Fil., t. 1, fig. 3. 
Oss.—The species of this genus present two very dis- 
tinct aspects, which form two groups. In the first the 
. lacine are plain, and often 1 inch or more in length, con- 
 Stituting the genus Mertensia of Willdenow ; in the second 
. the lacinæ are very small and revolute; these are by some 
termed true Gleichenia, but as the habit of growth of the 
_ two groups is the same, and there is not sufficient difference 
in the character of the sori to warrant their separation as 
 Eenera, I therefore arrange the species as follows :— 
| GLEICHENIA vera. (Calymella, Pr.). 
- Lobes of the pinnæ small, sub-rotund, generally revolute, 
Sporangia terminal. 
Sp. G. microphylla, R. Br. (v v.) ; G. dicarpa, R. Br. 
Vv.); G. semivestita, Labill. (v v.); G. hecistophylla, A. 
