216 
XVIII. BOTRTCHIfM. 
When at rest, the plant consists of a bud or hybemacu- 
luin. in which the incipient fronds are encased by brown 
membranous sheaths, the persistent bases of the fronds 
<>f former years. Enclosed in these sheaths the entire 
fronds are found in an embryo condition, but perfectly 
formed, with their two 
branches placed face to 
face, the fertile one 
clasped by the barren. 
Within the base of the 
growing frond of one 
year, are thus enclosed 
the rudimentary buds 
of the two following 
years. The stipes is 
erect, smooth, cylindri- 
cal, and hollow, with 
two or three bundles of 
woody fibre embedded 
in its succulent sub- 
stance ; at the base it 
is invested by the 
sheaths already alluded 
to; above, it becomes 
divided into two 
branches or pinnae, of 
which one is leafy and 
barren, the other fertile, 
both pinnate. The pin- 
nules of the leafy branch 
are smooth, glaucous 
ereen, Innate or flabel- 
fifonn, the margins ere- 
nate, or more or less deeply lobed; sometimes they be- 
come partially fertile, and they are occasionally pinna- 
rind, or linear and acute. The fertile portion is di- 
vided into branches corresponding to the pinnules. 
