422 STUDIES IN SEEDS AND FRUITS 



If fresh green acorns of full size and still vitally connected 

 with the cupule are placed in wet moss under warm conditions, 

 some of them will be found germinating within a week. 

 Nature's hint The germinative capacity of so-called unripe seeds does 

 gardener. not seem to have been fully appreciated by foresters, gardeners, 

 and horticulturists, the advantages to be derived from dispens- 

 ing with the rest-period being obvious. As subsequently 

 shown, nature offers us some valuable suggestions in this 

 direction in the case of the Oak. Many plants must afford 

 similar indications. Thus Pfeffer points out (ii. 205) that the 

 seeds of Senecio vulgaris and Stellaria media can germinate as 

 soon as they are ripe. Take again the soft, scantily protected 

 seeds of Pithecolobium filicifolium, the Bastard Tamarind of 

 Jamaica. They germinate a few days after falling from the 

 tree, or else lose their vitality altogether. 



The causa- The causes of the phenomena displayed in the resting of 



tion of the , , irii-ii>i-ri- 



rest-period, seeds must be sought tar back in the plant s lire-history, not in 



the seed alone, but in the seed as it depends on the fruit, and 

 in the fruit as it depends on the parent plant, and in the parent 

 plant as it responds to its conditions of existence. Therefore, 

 in dealing with the causation of the rest-period, we should 

 proceed in this order of investigation : the seed, the fruit, the 

 mother plant, and, lastly, the conditions. Yet it is at first 

 requisite to distinguish between the general causes that 

 determine the suspension of growth and the special influences 

 that determine the stage of development of the embryo at 

 which the rest-period is imposed. Any discussion of the 

 general causes must necessarily begin with an inquiry into 

 the influence of the fruit, and be then extended to the influence 

 of the parent, and then back to the conditions. Being un- 

 prepared to venture into such a wide field of investigation, 

 I will confine my remarks to the influence of the fruit, and 

 that only in an illustrative fashion. 

 The influence The biological disconnection of the seed indicated by the 



of the fruit __ r <. . -, 1 i V 



shrivelling or the runicle is proximately determined by the limit 

 of the fruit's vitality. The fruit dries, the funicle shrivels up, 



