CHRISTENSEN, ON SOME SPECIES OF FERNS. 29 
the hundreds of leaves examined by me. The leaf either ends 
in a terminal sorus or more frequently in a very hairy bud, 
by mean of which the leaf is long-living and capable of 
surviving an unfavorable season. — The hairs are very un- 
like those otherwise found in species of Hymenophyllaceae. 
They are very thick, red, cylindrical, consisting of two, ra- 
rely three cells, and are confined to the rachis and midribs 
beneath. 
The morphology of this little plant has been misunder- 
stood by Dr. Curist, who (Farnkr. d. Erde 23) describes the 
leaves as simple, sessile, in two rows on a axis, which is a 
branch of the creeping filiform stem. This interpretation is 
wrong. Curist’s leaf-bearing, lateral branches are not stems 
but leaves, which are pinnate with entire pinnae and some- 
times bearing a sorus at the very apex of the midrib. If 
CHRIST’s interpretation was the right one, this terminal sorus 
should be produced by a stem or at least a terminal leaf 
altered in a sorus; but sori-producing stems and terminal 
leaves are unknown. In some few cases I find the leaves 
definite, ending in a pinnatifid apex (fig. b); this would be 
an impossible thing, if Dr. CHRIST was right. 
The genus is probably monotypic with the single species: 
Serpyllopsis caespitosa (Gaud.) comb. nov. 
Syn. Hymenophyllum caespitosum Gaud. Ann. sc. nat. 
5: 99. 1825; Trichomanes caespitosum Hk. sp. fil. 1: 132 tab. 
40 B; Serpyllopsis antarctica v. d. B. Ned. Kr. Arch. 4: 377. 
1859 (syn.) 
A very variable species, but I have found it impossible 
to distinguish the following forms specifically. The differen- 
ces between them are evidently due to external conditions. 
The specimens from the alpine region of Fuegia and those 
from the humid forests of Guaitecas look very different in 
habit, but they show the same essential characters. 
1. typica (Hk. sp. tab. 40 B. fig. 1, 2); fig. 4 a—c. 
Small; leaves biserial scarcely 2 cm: long with a very 
short stipe or nearly sessile; lamina broadly ovate or oblong, 
lower pinn® not or a little shortened: pinne closely placed, 
horizontal or a little oblique, all sessile, generally boat-sha- 
