274 



STUDIES IN SEEDS AND FRUITS 



Viola. 



^Esculus 

 Hippo- 

 castanum 

 (Horse- 

 chestnut) 

 and Iris. 



comparative study of different fruits in all their stages. That 

 which concerns us here is the circumstance that Viola capsules 

 will dehisce under moist conditions without any drying what- 

 ever, and without any of the display of the results of elastic 

 tension which that process engenders. If we place a detached, 

 full-grown green fruit in wet moss, the first stage of dehiscence, 

 namely, the loosening of the cohesion between the valves, will 

 be accomplished without any drying, whilst the curling in of 

 the edges of the valves will be inhibited. 



This is what happened in my experiments on the fruits of 

 the Garden Pansy (Viola tricolor] ; and one may contrast with 

 such results, where dehiscence takes place without any drying, 

 those results for the same plant where drying plays a 

 prominent part in the opening of the capsule, as given below. 



THE DRYING AND DEHISCENCE OF A DETACHED RIPE CAPSULE OF 

 VlOLA TRICOLOR, WEIGHING FOUR GRAINS, THE RESULTS BEING 

 STATED IN PERCENTAGES. 



Again, if we take a number of full-grown but still closed 

 capsules of sEsculus Hippocastanum (Horse-chestnut) and of 

 Iris Pseudacorus, and place some in wet moss and others exposed 

 to the free air on a table, we obtain the following results. In 

 a few days several of those on the t&ble will be found to be 

 opening after losing 25 or 30 per cent, of their weight ; whilst 

 those in the wet moss which have not dried at all but have 

 probably added to their weight will be also dehiscing. The 

 detached capsules of Iris fcetidissima illustrate the same thing 

 more forcibly, since they dehisce in wet moss, but fail 

 altogether to open when allowed to dry. Drying, therefore, 

 though it develops strains, the relief of which ends in the 

 dehiscence of fruits, is not a necessity for their opening. It is 



