This peculi- 

 arity in 

 growth re- 

 presents the 

 first step 

 towards 

 vivipary. 



The drying 

 of the shell 

 in the ripen- 

 ing acorn. 



STUDIES IN SEEDS AND FRUITS 



the shrinkage of the coco-nut was satisfactorily explained by 

 the growth of its seed after the husk had begun to dry, I 

 began to examine in this light my data for the acorns of the 

 autumn of 1908. The growth of the kernel after the shell 

 had begun to lose weight and dry was unmistakably brought 

 out in the results of my weighings, as is shown in the table. 

 Further observation on the tendency to germination of the 

 acorn on the tree was made in the autumn of 1909 ; and 

 during September and October 1910 systematic weekly 

 observations and experiments were carried out on neighbouring 

 trees, leaving the original tree for the study of the viviparous 

 tendency. The results told the same story ; and their 

 indications were emphasised by those of fresh experiments on 

 the water-contents. It thus finally appeared that the tendency 

 of the seed of the ripening acorn to increase in weight after 

 the pericarp or shell has begun to dry finds its final expression 

 in the splitting of the shell and in the germination of the seed, 

 whilst the fruit is still attached to the cupule on the tree. It 

 was the first step towards vivipary, and a sign diagnostic of 

 the potentially viviparous habit of the oaks observed. Such is 

 the history of my researches in this connection. 



It is noteworthy that the observations made in 1908 are 

 in one respect more significant than those of 1910 in showing 

 how the seed of the acorn continues its growth after the shell 

 or pericarp has begun to lose its vitality and to dry, since 

 they were carried out with no special view in my mind. 

 But it is to the more systematic observations of 1910 that 

 I will now more especially refer, since the data there enable 

 us to compute the water-contents as far as they are shown 

 by the loss of weight of the materials when dried under 

 ordinary air-conditions. During the period between the 

 middle of September and the middle of October, the weight 

 of the seed increased from about 14 to 40 grains, whilst its 

 water-percentage decreased from about 70 to 40 per cent., 

 thus indicating a very marked addition to the solids as it 

 grew. But there was no such continuous growth of the shell 



