270 Murray and Boodle. — A structural and 
entering, or rather forming, the frond. If these three branches 
were increased in length below the frond they would produce 
an arrangement approaching that of *$\ pidcherrima. 
S. tenuis has a very minute stalk (Fig. 5 a), which bears a 
greater proportion to the frond as to length than is the case in 
vS. plumosa. It is smooth with a delicate wall, and below the 
frond there is a septum in the usual position, i.e. at a distance 
below the frond a little greater than the length of the lowest 
cell of the midrib. The stalk is unbranched except in one 
specimen, where it is forked about half way up ; one of the 
branches bears a frond, but the other is simple. 
The stalk of wS\ delicatula is never corrugated. It is simple 
or branched, and usually of about the same diameter as the 
midrib (Figs. 6 a, 7 a, 8 a ). 
The Roots of S. plumosa (Fig. 1 a) are given off laterally 
from the lowest auarter-of-an-inch of the base of the stalk ; 
they are very tenacious, branched, irregularly septate, occa- 
sionally transversely corrugated, bearing discs or tufts of root" 
lets here and there which are sometimes very like the organs 
of attachment to be described in the frond. The roots contain 
a great number of starch-grains and sometimes chlorophyll, 
even in the ends of their branches ; they become very much 
entangled and matted together, so that the stalks, which grow 
together in tufts, can often only be separated by tearing some 
of their roots. 
It seems very probable that vegetative multiplication may 
take place by some of the roots assuming the character 
of creeping rhizomes, which produce vertical frond-bearing 
branches. 
In support of this it may be mentioned that a root of 
.S. plumosa connected with a frond bore a vertical branch 
which, though small, was very like a young stem. S. macro - 
phylla has well-developed roots, but they have relatively thin 
membranes and an almost entire absence of cross walls, but 
numerous rhizoid attachments. The roots of 5 . delicatida are 
generally very septate and irregular (Fig. 8 c). S. ramosa has 
very slight development of roots in the specimen where the 
