46 
The Ferns of South Africa . 
except the terminal ones, which are six to fifteen inches long, one 
to three inches broad, tapering both to the base and to the point, 
and cut throughout, almost to the rachis, into linear pinnules one 
line broad, one to one and a half inches long, undivided, with a 
wide base, and a blunt or notched, or frequently one-sided point. 
The lowest pinnule on the lower side is generally elongated, and 
sometimes lobed, while at each forking of the branches arise a 
pair of small pinnae, two to four inches long, one half to one inch 
broad, divided into pinnules like the terminal pinnae, or lobed or 
sinuated, especially towards the base, but with the lowest lobe 
also enlarged. 
Sori of six to eight capsules, surrounding a raised receptacle, 
placed near the middle of a vein. The frond is glaucous on the 
under surface, and quite glabrous throughout on the Natal speci- 
mens, though it is described as being sometimes densely tomen- 
tose abroad, as well as changeable in cutting, but characterised by 
the small pinnae at the base of branches without pinnules. 
Gleichenia dichotoma, Willd ; Kuhn Fil. Afr. 167 ; Hk. and Bkr. Syn. 
Fil. 15. 
Mertensia dichotoma, Kunze, Linnsea 24, 247 ; Schk, Fil. tab. 148. 
Mesosorus, Haask. 
Found throughout the tropics, but known in extra-tropical 
South Africa only in Natal, where it was discovered by Gueinzius 
(fide Kuhn), and re-discovered in 1874 by Rev. J. Buchanan, at 
Umpumulo, “ on moist open slope, facing south, in bush near the 
top of a hill, two miles W. by S. of the mission station, about 
2500 feet.” 
Sub-Order II. — Hymenophyllacea:. 
Genus II. — Hymenophyllum. Hooker. 
Very delicate little plants, with creeping, and generally matted, 
slender rhizomes, growing in tufts on stones or trees, where there 
is constantly a saturated atmosphere. Fronds pellucid, consisting 
mostly of winged veins. Involucre terminal on some of the 
pinnules, composed of two flattened or concave valves, connected 
at the base, and containing between them the prolonged apex of 
