A Dictionary of Choice Ferns. 
233 
HYME.NOPnYL,LVM-contimed. 
H. Forsterianum. 
This beautiful species was accidentally introduce^! into 
this country growing among some clumps of Oattleyas im- 
ported from Brazil. At first sight it seems intermed'^ite 
betweein H. caudiculatum and H. dilatum, its large, 
handsome fronds, IJft. long and fully 6in. broad, being 
borne on stalks which are Gin. to Sin. long, conspicuously 
winged to the very base, and measure in the leafy portion 
quite ^in. in breadth. Their fronds are tripinnatifid, the 
leaflets, 3in. long, and not tailed like those of H. caudicu- 
latum, as well as their segments, being of a light green 
colour, closely set, and prettily undulated. The sori, two 
to six only on a leaflet, are terminal at the summit of the 
segments on the upper side only, and are provided with a 
very large covering, that is divided nearly to the base, and 
has broad, entire valves smooth on the edges. This is a 
very free-growing plant, whose wiry rhizomes are par- 
ticularly fond of moss and decaying vegetable matter. 
H. nitens, 
A synonym of II . flahellatum. 
H. nitidum. 
A synonym of H. flahellatum. 
H. tunbridgense. 
Though one of the smallest-growing species, the Tun- 
bridge Wells Filmy Fern is also one of the most interesting. 
It is not only in the British Isles that H. tnnhridgcnse is 
indigenous, for it is of a very cosmopolitan habit, being often 
imported from Madeira and the Azores, where it frequently 
covers the short trunks of Dicksonia (Balantium) culita. 
It is reported from the Mauritius, Jamaica, Venezuela. 
Guatemala, and the Peruvian Andes; it has also been 
found in Ceylon, on the Himalayas, &c. It is a 
compact, elegant little plant, with tiny, thread - like 
rhizomes of a very wiry nature, producing little fronds 
oblong-spear-shaped (Fig. 13, p. 18), lin. to Sin. long, 
^in. to lin. broad, and furnished with somewhat fan- 
shaped leaflets, divided nearly to the midrib on their 
upper side. The sori, which are stalkless and usually 
solitary in the axils of the narrow segments, are provided 
with a nearly round, two-valved covering, that is copiously 
toothed on the upper margin. Unfortunately, it is one of 
the most difficult of all Hymenophyllums to manage. It 
dislikes water over the fronds, and tlirives well either in 
a mixture of equal parts peat and silver sand or on a block 
of sandstone, the principal object being to have it pressed 
hard on to the material upon which it is intended to grow. 
