300 



PLANT LIFE. 



amination ; (3) upon the exteri<jr, one or Wo integuments 

 more or less readily distinguishable from each other (figs. 

 343^ 344, 345)- 



Fig. ^4;^, — Longitudinal section of fruit of bhick pepper, cnntainin)^ a single seed. /(.-, 

 pericarp, showing two layers (the outer unshaded, the inner shaded by radial lines); 

 sc^ seed-coats ; eiu^ embryo, surrounded by e"«, the endosperm ; _^, perisperm. Mag- 

 nified about 5 diam. — After Baiilon. 



Fig. 344.— Seed of pansy, entire and halved, the latter showing the straight embryo, 

 the endosperm (white and dotted), the seed-coats ; ?«, micropyle. Magnified about 

 10 d:ani — .After Tlaillnn. 



409. Fruit. — The growth of the embryo 

 excites not only the tissues of the o\-u]e to 

 further de\'elopnient, but also the sporophylls 

 (carpels) bearing the ovules, and not infre- 

 quentl}' even more remote parts. The carpels 

 and their contents and adherent parts, Miien 

 fully developed, constitute the fruit. The car- 

 pels are then laiown as the pericarp. The 

 changes which the parts undergo are chiefly 

 of two sorts — an increase in size and an altera- 

 tion of texture. The increase in size requires 

 no special explanation. The carpels may be- 

 come dry at maturity, or may thicken and become sol^t and 

 fleshy, or even juicy. In accordance witli these differences, 

 two sorts of fruits are recognized, namely, dry fruits and 

 flcshv fruits. ISetween these, however, there is no sharp line 

 of demari atiiin. 



410. Dry fruits. — If the pistil contain onh- one or two 



Fi.,. J, 5 ■ S,:ed 

 of piikeherry 

 ( Phytolacca, 

 d e c a n d r a ) ^ 

 halved ; show- 

 ing curved em- 

 bryo ne.xt the 

 two seed-coats 

 and nearly sur- 

 rounding the 

 endosperm. 

 Magn. about lo 

 diam. — .After 

 Kaillon, 



