THE PARTS OF A SEED-PLANT 317 
upon careful examination to be already a miniature plant, 
for it has a stem (s) bearing at its lower end the beginning of 
a root (r) which becomes apparent when the seed sprouts; 
while at the upper end of the stem are borne a pair of fleshy 
leaves (1) which after sprouting turn green, and between 
them a tiny bud (b) which is destined to grow into the stem, 
leaves, flowers, and fruit of the mature plant. Each of these 
parts of the embryo has been given a special name. The 
little stem which bears all the other parts is the cauwlicle.1 
Each of the first leaves is a cotyledon.2, The bud at the top 
of the caulicle is known as the pluwmule,? while the rudimen- 
tary root at the lower end is called the radicle.4 
93. The seedling and its development. When the seed 
germinates, the radicle is the first part to appear (Fig. 279B). 
Soon it grows into a root (Fig. 279C) covered with hairs 
through which absorption of soil-water takes place. Mean- 
while the cotyledons have been feeding upon the albumen 
to get material for their growth and for the elongation of the 
caulicle and root; and when finally this reserve food is ex- 
hausted, the empty seed-coat is cast off, the cotyledons become 
green and expand in the sunlight (Fig. 279D), and the plumule 
develops into a leafy shoot (Fig. 279E). As the root pene- 
trates downwards into the soil it sends forth branches in 
various directions (Fig. 2171). At the same time the leafy 
shoot grows upward developing stem and leaves by the con- 
tinual unfolding of a bud at its tip which began as the 
plumule (Fig. 279F). 
The place at which a leaf joins the stem is called a node,’ 
and the length of stem between two nodes, an internode.® 
1 Caul’i-cle < L. cauliculus, diminutive of caulis, stalk << Gr. kaulos, 
stalk. 
2 Cot-y-le’don < Gr. kotyle, a shallow cup, which some cotyledons are 
supposed to resemble. 
3 Plum’ule < L. plumula, a little plume, which the plumule of certain 
plants, such as the peanut or almond, somewhat resemble. 
4 Rad’i-cle < L. radiculus, diminutive of radix, a root. The term 
radicle is sometimes used so as to include the caulicle, and caulicle is 
sometimes made to include the radicle as above defined; but the terms 
are coming to be understood in the sense here adopted. 
° Node < L. nodus, a knot, the joint being likened to a knot in a cord. 
6 In-’ter-node < L. inter, between. 
