156 



FRUITS 



lucre, but the nuts, or true fruits, are not grown faso to it, 

 and the involucre can scarcely be called a part of the fruit. 

 A ripened ovary is a pericarp. A pericarp to which other 



parts adhere has 

 been called an ac- 

 '• cessory or reinforced 

 fruit. 



312. Some fruits 

 are dehiscent, or 

 split open at ma- 

 turity (279) and 

 liberate the seeds; 

 others are indehis- 

 cent, or do not open. 

 A dehiscent peri- 

 carp is called a pod. 

 The parts into 

 which such a pod 

 breaks or splits are known as valves. In indehiscent fruits 

 the seed is liberated by the decay of the envelope, or by 

 the rupturing of the envelope by the germinating seed. 

 Indehiscent winged pericarps are known as samaras or key- 

 fruits (consult Chapter XXIV). Maple, elm (Fig. 97), and 

 ash (Fig. 141) are examples. 



313. Pericarps. — The simplest pericarp is a dry, one- 

 seeded, indehiscent body. It is known as an 

 achene. A head of achenes is shown 

 in Fig. 268, and the structure is 

 explained in Fig. 207. 

 Achenes may be seen 

 in buttercup, hepatica, 

 anemone, smartweed, 

 buckwheat. 



314. A l-l0CUled 268. Achenes 269. 



.,.,,. of butter- Follicle of 



pericarp that dehisces cup . larkspur. 



267. Chestnuts are ripened ovaries. They are borne in : 

 prickly involucre. The remains of the catkin of stam- 

 inate flowers is seen in the picture. 



270. Young follicles of 

 larkspur. Normally, 

 the flower has 5 pis- 

 tils, but some are 

 lost in the struggle 

 for existence. 



