THE BATTLE OF LIFE AMONGt PLANTS. 
37 
victory. A few illustrations must suffice. It is easy to under- 
stand why first comers, duly installed, should have an advan- 
tage over later visitants; why the more prolific should out- 
number the less fertile ; and how it is that a perennial plant 
has a better chance on^ any given spot, cceteris paribus, than 
an annual whose progeny would find the ground occupied, and 
their chances of survival materially interfered with by their 
longer-lived neighbours. 
Again, there is no difficulty in understanding why such 
plants as quitch {Triticum repens) or bear bine {Convolvulus 
Sepium) hold their own so tenaciously and so much to the 
prejudice of their neighbours. The long creeping under- 
ground stems rooting, or capable of rooting, at every joint give 
them an immense advantage over plants not so favourably 
organised. The ends of the shoots of the convolvulus, more- 
over, dilate into tubers, which are thrust into the ground to 
form in the succeeding spring fresh centres of vegetation. A 
great rooting power is obviously of great benefit ; not less so 
is an extensive leaf surface. It is not only that the copious 
feeding roots absorb the available nourishment from the soil, 
not only that the wide leaf surface avails itself of every ray of 
sunlight, every whiff of air that plays over it, and thus serves 
to build up the tissues of the plant to which the root or leaf 
respectively belong, but they practically oust 'other plants less 
favourably circumstanced than themselves. The roots occupy 
the soil, and rob the weaker plants of their share of its 
resources. The tree with dense foliage shuts off from its 
lowlier neighbour much of the light and air necessary for its 
existence ; and hence, in a measure, the absence of vegetation 
in pine forests or under the shadow of dense woods.* Some 
plants there are specially organised to resist and overcome 
these hostile conditions. Among them are the climbers, the 
twining plants, and those with tendrils of one sort or another. 
The bramble or wild rose, with its slender, arching, hook- 
beset branches ; the wild hop, with its coils of cord-like sprays ; 
the clematis, clinging on firmly by means of its leaf-stalks to 
anything it can lay hold of ; the ivy, grappling with the trunk 
of a tree — all these are, in some sense, weakly plants ; they 
would be overweighted in the struggle with their stronger 
neighbours if it were not for the special adaptation of their 
structure just alluded to, and which enables them to bear their 
part bravely in the conflict. 
* These struggles were not unknown to ancient naturalists, as witness tl e 
following passage from Pliny, ‘‘Nat. Hist.” lib. xv. cap. 24: — ‘‘Necant 
invicem inter sese umbra vel densitate atque alimenti rapina . . . necat 
et edera vinciens, nec viscum prodest et cytisus necatur eo quod halimcu 
VQcant Graeci,” 
