HILUM,. 57 
CHAPTER IX. 
THE FRUIT. 
$2. OF THE SEED. 
117. Tue seed is the ultimate product of vegetation, and con- 
tains the rudiments of a new plant, similar in all respects to the - 
original. 
a. The seed consists of three principal parts;—the InTEGU- 
MENTS, the aLBUMEN, and the EMBRYO. 
118. The InrEGUMENTS, or coverings, invest the seed eee 
ately exterior to all its other parts. Although apparently single, 
they consist of several membranes, to each of which an appro- 
priate name has been applied. The first, or outer membrane, 
is the TEsTa; the second, the mEsosPERM; the third, the ENDO- 
PLEURA, Corresponding with the primine, &c. (90) of the ovule. 
a. 'The testa is either papery (membranous), leathery (coriaceous), horny (crus- 
taceous), bony, fleshy, or woody. Its surface is generally smooth, sometimes 
beautifully polished, as in the Indian shot (Canna), or columbine, and often 
highly colored, as in varieties of the bean, &c. It is sometimes expanded into 
wings, as in the Arabis, and sometimes into a tuft of hairs at one end, called 
coma, as in the silk-weed, or it is entirely enveloped in hairs, as in the cotton. 
b. The coma must not be confounded with the pappus (99, a), which is a modi- 
fication of the calyx, appended to the pericarp, and not to the seed, as in the 
achenia of the thistle, dandelion, and other Composite. 
119. The ard is an expansion, proceeding from the summit of * 
the funiculus, or seed-stalk (91), (or from the placenta when 
the funiculus is wanting) either partially or wholly investing 
the seed. A fine example is seen in that gashed covering 
of the nutmeg, called mace. In the celastrus it completely 
envelops the seed. In other seeds it is a mere scale, and often 
it is wanting. 
120. The uitvm, or scar, is that point or mark left on the coats 
of the seed, by its separation from the funiculus (stalk). It is 
commonly called the eye, as in the bean, pea, maize, &c. (Fig. 
EE3.6)..@:) ~ 
121. The hilum of the seed sometimes corresponds with the chalaza of the 
