4 CLASS-BOOK OF BOTANY. 
stock in addition to the tuft of radical leaves, and ele 
these—at distances of a few inches—produces eee eo 
account of the leaves being thus produced singly Hi cia eee 
stem and alternately with one another them eA een a 
is called alternate. The part of a stem or branch a ga . 
leaf is produced is called a node, and the portion le eee 
between any two nodes is an internode. You will observe 
that some of these branches stand upright and produce Sok 
while others trail along the surface of the ground. Notice also 
that at each node on these trailing branches there is a more 
or less evident thickening, and, while a tuft of leaves is given 
off on the upper side, there is occasionally also a tuft of root- 
fibres sent downwards, thus attaching the branch to the 
ground. ‘The tuft of leaves is itself a secondary branch, 
closely resembling the central one in structure, and it arises in 
the angle made by the creeping stem and the leaf at whose 
‘node it is produced. This angle is called the leaf-axil, and 
the secondary branch is therefore said to be axillary. This, 
then, is one of the modes in which our plant propagates itself— 
namely, by sending out creeping stems which root at the nodes 
and thus form new plants. 
The upright branches also produce leaves at intervals 
(called from their position cauline leaves), and secondary 
branches in their axils. Observe further that nearly all parts 
of the plant except the.roots and the inner portions of the 
flowers are covered with white hairs, which are shortest and 
most numerous on the leaf-blades. These hairs presumably 
serve to protect the soft eatable parts of the plant against the 
attacks of certain leaf-eating insects. 
Let us now examine the leaves, taking a radical leaf first. 
Notice that it has a very long stalk or petiole, and terminates 
in an expanded green portion—the blade or lamina. The 
very lowest portion of the petiole is widened out on each side 
into a wing-like base with which it sheathes the rootstock. The 
blade itself is divided into three separate leaflets, and is hence 
called trifoliolate.* (Pl. I., fig. 1.) (The general term com- 
pound is applied to all leaves which have more than a single 
blade on each petiole.) Hach of the leaflets is further divided, 
usually into three lobes or segments, and these segments haye 
their margins more or less deeply toothed or dentate.{ The 
cauline leayes become more and more reduced in size the 
Aigher up the stem they are produced. Those lowest down 
‘the under-side; \Generally each leaflet. has three’ main veins, Oe) 
have the same general form as the radical leaves, but with 
shorter petioles, while those highest up of all have no petioles, 
* Lat. tris, three ; foliolum, a little leaf, 
T Lat. dens, -tis, a tooth. 
