2C>6 



STUDIES IN SEEDS AND FRUITS 



and Guilandina bonducella. The swollen seed ready for ger- 

 mination is rather smaller than the pre-resting seed of the 

 ripe moist pod. Its coats are tougher and drier, holding in 

 one instance 23, and in two instances 13 per cent, less water 

 than in the pre-resting condition. Yet within these tightened 

 relatively unyielding envelopes lies in each case a kernel that 

 is about 20 per cent, heavier through the absorption of water, 

 and correspondingly larger than in the pre-resting state, a 

 condition of strain necessarily resulting. 



As a rule the conditions of strain within the swelling seed 

 are at first rather more pronounced in permeable than in imper- 

 meable leguminous seeds. This is well shown in the average 

 results for these two types of seeds already given on a previous 

 page. But in the case of the permeable seed the relatively 

 thin coverings soon give way, whilst with the impermeable seed 

 the tougher and thicker coats resist the strain of the swelling 

 kernel for many days, and the strain, though less at first, 

 becomes very great when the swelling of the kernel is far 

 advanced. 



It occasionally happens with impermeable seeds that the 

 conditions of strain are intensified from the beginning, and, as 

 in the case of the seed of Mucuna urens, a somewhat abnormal 

 regime is displayed. Whilst its coats behave like those of a 

 permeable seed, its kernel plays the r61e of a seed of its type, 

 but in an exaggerated fashion. 



The regime of 

 Mucuna urens 



Coats : pre-resting 100, resting 28, swollen for 



germination 43. 

 Kernel : pre-resting 100, resting 70, swollen for 



germination 152. 

 Entire: pre-resting 100, resting 50, swollen for 



germination 100. 



Whilst studying this seed in the West Indies, I noticed 

 that the complete soaking of the coats was not requisite for 

 germination, the radicle often protruding through coverings 

 partly dry. This occurs occasionally with seeds like those of 

 Dioclea reflexa and Entada scandens. In some other leguminous 



