SEXUAL REPRODUCTION. 2i\ 



chambers are exceedingly various. In some cases the open- 

 ings are so small as to be mere slits or pores (fig. i88). In 

 others a more or less circular line of breakage forms a little 

 door or valve which opens and closes with changes of moisture 

 (fig. 189). In other cases the pericarp splits lengthwise into 



Fig. 188. Fig. 189. 



Fig. 188. — Ripe capsules of a wintergreen {Pyrola chlorantka)^ showing dehiscence 

 by pores. The opening is a short split at the middle of the base of each carpel. 

 ^ Natural size. — After Kemer. 



Fig. 189. — Ripe capsules of a bellfiower (Crtwz/rtwM/fl ra^unculo/'des), showing small 

 reflexed valves. Natural size. — After Kemer. 



two or more pieces (fig. 190), or, less often, cracks trans- 

 versely so as to loosen a lid (fig. 191). 



308. Fleshy fruits. — The changes which produce flieshy 

 fruits consist in a transformation of certain parts of the peri- 

 carp into masses of thin-walled juicy cells. Other parts may 

 remain unchanged, or may even become hardened. The 

 inner part of the pericarp sometimes becomes of a stony hard- 

 ness, while the outer portion becomes soft and juicy. Such 

 changes produce a fruit like that of the peach or the cherry. 

 The pericarp encloses a single seed with delicate brown seed- 

 coats whose protective function has been completely usurped 

 by the stone (fig. 192). In other cases, while the inner face 

 becomes stony, the outer becomes fibrous, tough, and dry, as 



