246 



STUDIES IN SEEDS AND FRUITS 



Comparison 

 haviour of 



thoseofother 

 fruits. 



First, 



Hippo- 

 castamim). 



This table supplies a means of comparing the behaviour 

 during the maturing and drying stages not only of the seeds 

 ^ ^ er kinds of fruits, but of the fruits themselves, and 

 particularly of the capsule and the leguminous pod. 



We will first take the Horse-chestnut (&sculus Hippo- 

 castanum\ which almost acquires the baccate habit, though its 

 familiar condition, as it lies open on the ground, is that of a 

 dryish dehiscent fruit. The same preliminary shrinking of 

 the seed, associated with hardening and " browning " of the 

 seed-coverings, takes place in the closed capsule. These 

 changes, however, only occur in the last stage of maturation 

 immediately preceding dehiscence. As the green fruit mellows 



with maturity it becomes yellowish, and it is during this 



,1 , , , - , 



mellowing stage that the shrinking, hardening, and browning 



of the soft white seed take place within. 



If the soft white seed is removed and allowed to dry in 

 the air, its coats rapidly harden and assume the characteristic 

 reddish-brown hue, a change which experiment showed to be 

 associated with a loss of 17 per cent, of the original weight. 

 The hardening and coloration of the coverings were completed 

 in twenty-four hours, when the seed was placed in a warm, dry 

 cupboard ; whilst in diffuse light in a damp room they occupied 

 two or three days, an indication that these changes are the result 

 of partial drying only and do not require the action of light. 



If we wished to designate the particular stage in the 

 maturation of the capsule of the Horse-chestnut correspond- 

 ing to the ripe berry, we should select the mellowing stage 

 immediately preceding dehiscence, when the green capsule 

 assumes a yellowish tinge. It is then, and we are now 

 indebted to the clue supplied by the seeds of the Herberts berry, 

 that the seed undergoes its preliminary shrinking and that the 

 hardening and colouring of its coverings within the closed 

 capsule occur. Like the seeds of the berry also, it has yet 

 much more water to lose. It has been already implied that as 

 soon as the capsule begins to open it displays a well-browned, 

 hard-coated seed (or seeds), which, as indicated by an experi- 



