KEYS TO THE FERNS OF BORNEO 
419 
caudex; or it may be creeping or climbing, in which case, 
it is called the rhizome. The rhizome is in general botany 
restricted to prostrate under-ground stems, but in the case 
of ferns is applied to all stems which are not erect and 
conspicuous. Such expressions as “ Rhizome erect” are 
> » 
common in systematic work on ferns. The rhizome may 
be short, in which case, the leaves are clustered or it may 
be very long, and bearing the leaves at considerable 
intervals. The rhizome is always provided with a coat of 
scales, and these scales, technically called paleae if notice¬ 
ably wide, are very important in classification. They 
may be persistent or may be deciduous, in which case the 
rhizome becomes naked or glabrous, but the scales can 
always be found near the apex. In form, they vary from 
hair-like, in which case they may be spoken of as hairs, to 
very broad. The terms, applying to their forms, apices, 
bases, and margins have the same meaning that they have 
when applied to leaves or leaflets. 
The leaf of a fern is called the frond. This word is 
used in two senses:—first, as applying to the entire leaf; 
and second, as applying to the blade, or green and expan¬ 
ded part of the leaf. The latter sense is preferable and is 
the one used in this paper. A complete leaf consists of 
three parts : stipules, stipe or petiole, and the frond proper. 
The Marattiaceae bear large, fleshy stipules; all other 
ferns are without them. The stipe may be wanting, in 
which case the frond is said to be sessile. If the green 
part of the frond, the lamina, runs down along the sides of 
the stipe, the stipe is said to be winged. The stipe may 
be round (terete), or is more frequently channeled on the 
upper side. The stipe may be glabrous, or it may bear 
paleae of various forms, and it may also produce true hairs. 
Epiphytic ferns are exposed to danger from want of water. 
