THE UNILATERAL FILM FERN 
Fronds smooth, ређи accous, minutely cellular, dark green, from one or two, to five or 
te-oblong, pinnate, Pinna decurrent in the upper part 
and there forming a narrow wing to the rachis; distinct below; curved backwards, subunilateral 
weds otomously forked, 
without an axial vein, the segments the anterior si 
Ultimate segments linear, obtuse 
spinulosely serrate, Luxuriant fron deney to become branched. 
vo or three dichotomous ramifications of the wiry ribs, which branch alter 
nately from the main rachis; each ultimate 
ament having one of these branches along its cent 
not quite reaching to the apex 
Fructification produced on the upper parts of each annual growth, extra-marginal as im 
il 
H. tunbridgense. Sori consisting of cases, clustered around the short 
veptacle, Jt 
p 
tacte freo, central, sj т than the valves of the involucre, Zneolueres 
agy, oblong, elub-shaped, sh 
supra-axillary, more or less ob stalked, curved forwards, i. e. in a direction opposite to that of 
the segments; inflated, two-valved, the valves ovate-oblong, strongly convex, and quite entire at the 
edges, which aro at first closed, but at length become Spor sessile, vertically com 
pressed, thus lenticular, obliquely affixed. Spores minute, irre In some instances, 
especially where the frond becomes branched at the apex, numen 
H. tunbridigen 
nents, but 
usually they are confined to one on each pinna, next the rach 
Duration, "The rhizome is perennial. The fronds are perennial, enduring for two or three years, 
or more, renewing their growth annually, as occurs in Lycopodium annotinum, 
We are indebted to Mr, F. Clowes, of Windermere, for the interesting observat 
т that the fronds 
of this species of Hymenophyllum resume their growth after the first year, unlike those of J. tun- 
bridgense, which complete their growth in or 
Mr. Clowes gives the following account of his 
observations :—“1 
а largo plant of IZ t and of JI. unilaterale, which were put into 
п case in March, 1854. Both are growing vigorously. But I remark that all the fronds of 7. tunbrid. 
gense are annual—T mean, they come up in spring, bear fruit more or less, persist more or less, but 
never grow more than one year. ‘Those of M. unilaterale, on the 
year. A great number of the fronds which were on the plants when placed in the case went on 
growing, bore fruit at or near the extremity of the fronds that year 
bore fruit, and are doing the same this year (1850), so that 
me {то inches long, and 
wide in proportion. This is not the effect of cultivation, as the wild plant does exactly the same— 
nously in faet, but without distinet marks between the growths. 
The cultivation of the Film Ferns is an object of much interest to the fanciers of British Ferns, 
The plants require a glass covering to preserve about them a const 
ould be maintained about their roots, These are their main 
id it matters little how they are applied, whether in a W 
common bell-glass. We learn from Mr. Clowes, wh 
success is evident from his remarks already 
quoted, that the bell-glasses ou 
ass, Until he 
with but little success. 
а small apertures, as vonts, near the top of 
the gl pted this expedient, his efforts to cultivate the Film Ferns were attended 
m 
