57 



CHAPTER IX. 



THE FEUIT. 

 §2. OF THE SEED. 



117. The seed is the ultimate product of vegetation, and con- 

 tains the mdiments of a new plant, similar in aU respects to the 

 original. )^ 



a. The seed consists of fou-ee.)principal parts ; -^the integu- 

 ments, the ALBUMEN, and the embryo. ' 



118. The Integuments, or coverings, invest the seed immedi- 

 ately exterior to aU its other parts. Although apparently single, 

 they consist of several membranes, to each of wloich an appro- 

 priate name has been apphed. ] The first, or outer membrane, 

 fs the testa; the second, the mesosperm; the tliird, the endo' 

 PLEURA, con-esponding with the primine, &c. (90) of the ovule, i 



a. The testa is either'papery (membranous), leathery (coriaceous), homy (crus- 

 taceous), bony, fleshy, or woody.S Its surface is generaUy> smooth, sometimes 

 beautifully poUshed, as in the Indian shot (Canna), or columbine, and often 

 highly colored, as in varieties of the bean, &c. jit is sometimes expanded into 

 wings, as in the Arabis, and sometimes into a tuft of bans at one end, caUed 

 coma, as in the sHk-weed, or it is entu-ely enveloped in hau-s, 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 pericai-p, and not to the seed, as in the 

 achenia of the thistle, dandelion, and other C»mposit£e. 



119. The aril i&,an expansion, proceedmg from the summit of 

 the funiculus^ or seed-stalk (91), (or from the placenta when 

 the funiculus^is wanting) either partiaUy or whoUy investing 

 the seed. A fine example is seen in that gashed covering 

 of the nutmeg, caUed mace.'. In the celastms it completely 

 envelops the seed. In other seeds it is a mere scale, and often 

 it is wanting. 



120. The hilum, oi* 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. 

 11; 8, a.) 



i21. The hilum of tlie seed sometimes corresponds with the chalaza of the 



