WOOD KQUISETUM. 
(Jl 
clothed with fibnlloe : the rhizoma is horizontally extended, 
branched and striated ; in many places it is clothed with fibrillse 
like those of the roots : it is throughout of a dark brown colour. 
The stems are of two kinds, fertile and barren : both, when 
mature, are usually furnished with compound branches. The 
fertile stems rise from the ground perfectly naked, but most of 
them soon exhibit incipient branches just at the base of the 
upper sheaths ; these quickly elongate into compound branches, 
forming several whorls : a few of the stems remain unbranched, 
and quickly disappear. The number of whorls varies from two 
to eight ; I have rarely met with the latter number, and never 
with more. Long after the catkin has decayed, these whorls of 
branches continue vigorous for a short time, and combine in 
giving a blunt appearance to the entire frond. The stems are of a 
dull, sickly, green colour, succulent and striated : the striae are 
about twelve or fourteen in number, and the ridges between 
them are armed with minute siliceous points, but these are in- 
sufficient to communicate much roughness or harshness to the 
plant. The sheaths are very long and loose, terminating supe- 
riorly in three or four large conical lobes, containing on an ave- 
rage three striae in each; the inferior portion of these sheaths is 
concolorous with the stem, the superior or apical portion is of a 
bright russet brown colour. 
The catkin is elongate, somewhat pointed, and of a pale brown 
colour ; it stands on a slender stalk, of rather more than its own 
length. The scales of the catkin are eighty and upwards in 
number. The catkin is ripe in April. 
The barren stems are about eighteen inches in length, and 
make their appearance almost simultaneously with the fertile 
ones, but are more slender, and the sheaths are much smaller, al- 
though similarly formed and coloured. The whorls of branches 
are from ten to twenty in number, and the branches composing- 
each whorl gradually decrease in number and length towards the 
apex, which is extremely slender, so much so, that unable to 
bear its own weight, it droops on one side, and is not readily 
to be distinguished from the surrounding branches. The striae are 
more distinct than in the fertile stem ; three or four of the ridges 
run into each of the lobes of the sheaths, and unite in its apex. 
