98 



THE FRUIT : DISPERSAL OF SEEDS 



it dehisces along both the dorsal and ventral lines (Fig. 37). 



The pods of peas and beans are examples. 



(iii) The siliqua (Fig. 44) is an elongated 

 superior fruit composed of two united carpels. In 

 the interior of the fruit is a thin false dissepiment or 

 partition, termed the replnm^ which separates the 

 fruit into two chambers. When ripe the two carpels 

 dehisce from below upwards and leave the seeds 

 attached to the placentas and replum. Examples 

 Fig, 43.— Foi- are met with in the turnip, cabbage, and wallflower. 



Vm&°AgKii^a-) The term silicula is applied to fruits of this descrip- 



cence°afong''one tion which are short and broad as in shepherd's 



suture. pyj.gg_ 



(iv) The term capsule is generally applied to practically all 

 forms of syncarpous, dry dehiscent fruits except those just men- 

 tioned. They may be either superior or inferior, 

 and usually contain many seeds. The manner 

 and amount of dehiscence is very varied : most 

 frequently it is longitudinal, but in some cases 

 it is transverse. The dehiscence may extend a 

 part of "the way along the fruit and the carpels 

 remain partially united with each other ; or it 

 may extend the whole length of the capsule and 

 the carpels become free and fall away from each 

 other. If the latter happens and the splitting 

 takes place along the dorsal suture, the dehiscence 

 is described as locuUcidal; the term sepiicidal is 

 used when the dehiscence occurs along the line of 

 union of the carpels. 



In some cases the outer parts of the capsules 

 fall off as separate pieces or valves leaving the partition or septa 

 of the gynascium attached to the flowerstalk : such dehiscence 

 is described as septifragal. 



Dehiscence by pores is seen in the capsules of the poppy. 



Fig. 44. — Siliqua 

 of wallflower, 



showing manner 

 of its dehiscence ; 

 V valves of. fruit ; 

 r replum with seeds 

 attached (c/C Fig. 

 123)- 



