INTRODUCTION 
Branches 
The Leaf 
As the branches of a stem are merely secondary stems they resemble 
primary stems in all particulars save in their lateral origin ; and, as they 
originate in the axils of leaves, their arrangement is mainly 
dependent upon that of the leaves, though every axillary 
bud does not develop into a branch. The general outline of a plant 
is obviously dependent upon the number, arrangement, and vigour of 
its branches. While, as we have said, in some plants, branches may 
develop into tendrils, in others they become short, rigid, pointed structures, 
known as spines , as in the Blackthorn, Gorse, and Buckthorn. Less 
commonly they may be flattened out into a leaf-like form, as in the 
Butcher’s Broom, when they are known as phylloclades (Greek 4>v\Xov, 
phullon , a leaf ; k\ aSo?, klados , a branch). 
A great number of differing parts of a plant are constructed on the 
leaf type, or are, as is often said, modified leaves. Among them are leaves 
concerned in the protection or nutrition of the individual 
plant, and others, known as floral leaves , concerned directly 
or indirectly in seed-production ; but all alike originate in definite order 
on a stem from its base towards its apex, or, as it is termed, in acropetal 
succession (Greek dxpov , akron, summit ; Latin peto , I seek), as lateral 
appendages, generally differing in form from the stem that bears them. 
Thus in the earliest stages of the life of a flowering plant the seedling 
has one or two cotyledons, or seed-leaves, which may either remain in the 
seed as mere storehouses of nutriment, or may rise above ground, become 
green, and so serve as the first foliage-leaves. These are generally smaller 
and of more simple outline than the leaves developed later, as, for example, 
in Mustard and Cress, which are eaten as salad in this seedling stage, or 
in the strap-shaped cotyledons of the Sycamore. 
Underground stems and the stems of many parasitic plants, such as the 
Broom-rapes ( Orobanche ), and saprophytes (Greek oranpos, sapros , rotten ; 
Pvt'ov, phuton, a plant), i.e. plants living upon decaying organic matter, such 
as dead leaves — of which the Bird’s-nest Orchis is an instance — bear reduced 
scale-leaves , membranous or fleshy, and not green. Somewhat similar are 
the bud-scales that enclose the winter buds of perennial plants and are thrown 
XXI 
