68 AMERICAN FERN JOURNAL 
2 to 6 inches in length. TJ. Krausii may be regarded 
as a transition from the simple type to the generalized. 
These two types hold sway from 1000 to 4000 feet in 
elevation, the latter being represented by 7. pyzidi- 
ferum, T. arbuscula, H. polyanthos, H. tunbridgense, 
H. fucoides, and H. catherinae. The character of the 
frond diverges from the generalized type toward both 
a finer and a coarser segmentation. H. avillare and 
H. crispum are close to the generalized type but rather 
finely dissected, the ultimate segments of the latter 
being elaborately frilled. 7. tenerum has narrow elong- 
ated fronds with very narrow segments, and grows only 
as a pendent epiphyte on the trunks of tree ferns. The 
most finely dissected of all Trichomanes is T. trich- 
oideum, which has fronds from 2 to 3 inches in length, 
with fine capillary segments less than 2 inch in diameter. 
One of the most striking sights of the rain-forest is a 
tree-fern trunk covered with an airy mat of Trichomanes 
trichoidewm, from which glisten a thousand drops of 
water held in the forkings of the fronds. 
The finely dissected filmy ferns are outnumbered, at 
least in Jamaica, by those in which the ultimate seg- 
ments are wider than in the generalized type. Hardly 
any of these have as large areas of unbroken leaf sur- 
face as may be found in the simple types first men- 
tioned, but all are much larger than the simple types, 
so that some of them have a total area of as much as 
6 square inches. This is true of T. crispum, a simply 
pinnate form growing erect and stiff on the ground or 
as a low epiphyte. The pendent H. asplenioides has 
glabrous fronds of simple form and sinuate outline with 
rather large areas of solid leaf surface, and there are 
also large areas in T. alatum and T. crinitum. 
In the majority of the more coarsely segmented fronds, 
and in some of the generalized type, we have a more or 
less pronounced hairiness. This results in a brownish 
