53 
r 
appear to live. Where this sedge grows abundantly its runners are 
to be found crossing and recrossing beneath the surface, and careful 
excavation will show that many seemingly distinct plantlets belong 
to one system of underground stems, in some soils the plant grows 
more compactly than normally, and few runners are produced. In 
more favorable situations the runners are numerous, and many strike 
down diagonally into the earth, proceeding some inches before turn- 
ing upward to the surface to bear a,shoot. 
The runners are at first clothed with closely imbricated scales or 
paleae arising from nodes all along the stem. These scales ultimately 
decay and become frayed into a coarse fringe, which remains 
appressed to the stem in whorls from every node. 
In Carex varia we find a very different habit of growth. This 
species never produces running underground stems, and shows no 
disposition to spread, but grows in close tufts. Beneath the surface 
It develops a dense, knotty mass of small and closely aggregated 
rootstocks which bears a profusion of long fibrous roots. Year after 
year these rooty masses produce an abundance of new shoots, which 
rise from the surface amid the remains of the old. Each ultimate 
rootstock becomes the site for a cluster of compound shoots, and 
these secondary tufts, compacted together, make up the plant. A 
slight lateral prolongation of a shoot is sometimes necessitated by an 
obstruction in the most direct way to the surface, but this is the 
closest approach to subterranean spreading, and thus we find the 
plant forming neat, even-bordered tufts, there being no offshoots- to 
niar the symmetry of outline. 
In C. Pennsylvanica a slenderness of general habit is associated 
with a certain liberty of growth— a distribution of vital energy ; in 
C varia similar vegetative conditions are contracted, and somewhat 
modified in action, resulting in greater solidity of growth and increase 
in the size of parts. We may say that in the principle of growth of 
one we perceive decentralization, enterprise, advance in many direc- 
tions; of the other, centralization, conservatism, unified strength. In 
none other of our species of Carex of the section Montance do we 
find the counterpart of the running underground stems of C. Penn- 
sylvanica. The closest approach to them is shown by Carex umbellata. 
From its dense, matted tufts, this sedge occasionally puts off short 
underground stems. These, however, are more like suckers than 
funning stems, and never stray from the main tuft, but merely aid in 
increasing its dimensions. Carex pubescens is of less tufted habit 
than any of the other species of this section, the shoots being irreg- 
ularly produced by a progressive underground stem or rootstock. 
But this bears no resemblance to the running stems of C PennsyU 
'^'(tnica, being rather stout, with short, irregularly-branched divisions. 
Our only other species, Carey. Emmonsii, is of very similar under- 
ground growth to C varia, the difference, in fact, corresponding to 
the general difference between the superterrene parts of the two plants. 
Riverdale, N. Y. City. Eugene P. Bicknell. 
Survival of the Fittest.-When we use this expression it may be 
*en to remember that accident has quite as much to do with fitness 
