THE FRUIT. 197 



Fig. 92. 



state of maturity, the pericarp opens to let the seeds escape. 

 The fruits which open spontaneously in this manner are said to 

 be dehiscent, (dehisco I gape). However, there are some fruits 

 which fall to the ground without opening or dehiscing. The 

 fleshy pericarps of the peach and apple for example, do not 

 open ; their seeds are liberated as the fruit decays. The dry 

 pericarps of the Compositse, the Maize, and the Ranunculus, 

 remain indehiscent on the soil, enveloping the grain till the 

 plantule in germinating forces a passage through them. 



The pericarp, whether it proceeds from a single pistil, or 

 from one that is compound, always presents on its outer surface 

 longitudinal lines which are called sutures. One of these 

 sutures, formed by the union of the free margin of each carpel- 

 lary leaf, is called the ventral suture ; the other, exactly oppo- 

 site, and corresponding to its midrib, is named the dorsal 

 suture; the former is generally connected with the axis, the 

 latter with the periphery of the fruit. In a simple pericarp, 

 such as the pod of the pea, for example, both these sutures are 

 equally visible on the exterior of the fruit. But when the 

 carpels solder together by their lateral surfaces, and form a 



