DEHISCENT DRY FRUITS 97 



(ii) The achene is a one-seeded fruit, with a thin leathery peri- 

 carp ; it is the product of an apocarpous superior ovary. Examples 

 are seen in the buttercup (Fig. 226), rose, and strawberry. 



In the rose, the achenes or true fruits, are enclosed within 

 the hollow receptacle which, when ripe, is scarlet and soft. 



In the strawberry the receptacle is succulent, the true fruits 

 being the small achenes studded over it (see Fig. 125). 



(iii) The caryopsis is a superior one-seeded fruit resembling 

 an achene, but the seed within it, instead of being free as in the 

 latter, is united with the wall of the pericarp. The fruits of 

 grasses are caryopses. 



(iv) The samara resembles an achene, but the pericarp is 

 furnished with wing-like appendages, e.g. ash, elm and sycamore 

 (a double samara). 



II. Schizocarps. 



These are dry syncarpous fruits, the united carpels of which, 

 when ripe, separate from each other, but do not set free the 

 contained seeds as in the dehiscent fruits mentioned below. 

 Each separate carpel of the fruit is termed a mericarp, and 

 usually contains a single seed enclosed within it. 



Sycamore fruits, and those of the carrot, parsnip, and other 

 Umbelliferae, are examples of schizocarps (see Fig. r34). 



III. Dehiscent Dry Fruits. 



In these the pericarp splits in various ways or opens by pores. 

 The interior of the fruit is exposed, and the seeds, which usually 

 have thick protective testas, are set free. 



Most dry fruits of this class have many seeds. 



The commonest forms of dry dehiscent fruits are mentioned 

 and described below. 



(i) The follicle is a superior fruit consisting of a single carpel 

 which opens along one suture only, most frequently the ventral 

 one. Columbine fruits are examples (Fig. 43). 



(ii) The legume is also a superior fruit of one carpel, but 



G 



