STUDIES IN SEEDS AND FRUITS 



Dther 

 ndications. 



Working 

 hypotheses. 



precatorius that gave direction and method to my inquiries. 

 Noticing that the large, soft, unripe seeds of the green un- 

 opened pod were three times the size and double the weight of 

 the normally contracted hard seeds of the dehiscing pod, I 

 found that a large, soft, unripe seed weighing 3 grains lost i^ 

 grains of water when drying and entering the resting state. 

 This, I argued, would be the water that the resting seed would 

 take up when swelling for germination ; and it thus appeared 

 that in preparing for germination, a seed was merely resuming 

 its original unripe condition. But it was to the phenomena of 

 the shrinking process that my opportunities at first restricted 

 my attention during the early part of 1907 in Jamaica. Ob- 

 servations on the seeds of Casalpinia sepiaria^ Canavalia ensi- 

 formis, C. gladiata, and C. obtusifolia, led me to distinguish a 

 critical period in the shrinking process which roughly coincided 

 with the shrivelling of the cord or funicle, and the severing of 

 the biological connection. 



When the soft, unripe, though full-sized seed was detached 

 before the cord began to shrivel, it lost 70 or 75 per cent, of 

 its weight in the drying and shrinking process ; but if the 

 detachment was effected after the cord had commenced to 

 wither, but before any drying of the seed was evident, then 

 the subsequent loss of weight was only about 50 per cent. 

 The result in the first case was a shrivelled seed ; in the second 

 case a normal resting seed. Now I assumed that the difference 

 between the two losses in the drying stage, viz. 20 or 25 per. 

 cent., represented the water retained by the resting seed for 

 the support of the embryo, and I termed it "the water of 

 inclusion." In forming this inference I was also influenced by 

 the results of simultaneous observations on the seeds of other 

 plants, such as those of the Bastard Tamarind {Pithecolobium 

 filicifolium) ; but I need not here particularise them further. 



My attention became then directed more especially to the 

 observation of the shrinkage of the soft, unripe, or uncontracted 

 seeds of two leguminous climbers, Entada scandens and 

 Mucuna urens, very favourable opportunities being aflForded 



