1 66 STUDIES IN SEEDS AND FRUITS 



(3) That with variable seeds, where there is a mixture of 

 permeable and impermeable seeds, the range is inter- 

 mediate in amount, frequently about i per cent., but 

 varying of course with the proportion of permeable 

 seeds. 



With those " variable " seeds, as with Entada polystachya 

 and Ctesalptnia Sappan, where it is possible to distinguish by 

 inspection between the two types of seeds, the difference in 

 the hygroscopic reaction is well marked. Thus, with the 

 first-named plant, a sample of permeable seeds displayed a 

 range of 2 per cent., whilst a sample of seeds almost all 

 impermeable gave a range of 0*2 per cent. So also with 

 Ctesalpinia Sappan, I found that seeds which had fallen to 

 the ground in the ordinary way were mostly impermeable 

 and had a range of cr6 per cent. ; whilst those remaining in 

 the dried but closed pod on the tree were nearly all permeable 

 Thehygro- and varied 3 per cent, in their weight. It would be quite 

 action as" a possible for the gardener or the agriculturist to devise a 

 V ~ rou g n an< ^ re ady rule by which the proportions of hygro- 

 scopic permeable seeds and of non- hygroscopic impermeable 

 seeds in any sample could be approximately estimated. Thus, 

 assuming that with seeds of a certain kind the complete 

 hygroscopic reaction when all the seeds were permeable was 

 3 per cent., then a sample of the same seeds that gave a 

 range of 1*5 per cent, might be regarded as probably contain- 

 ing only 50 per cent, of permeable seeds. At all events a 

 marked departure from the normal might give a valuable hint 

 to the gardener in making a selection. 

 The influence The influence of the coats in restraining the hygroscopic 



nf i"Vi* dppH 



coats on the variations of permeable seeds has already been briefly alluded 



scopitity of to i n Chapter IV. It was there shown that the hygroscopic 



permeable range of the seed of Canavalia ensiformis with its coats intact 



(2'5 per cent.) was less than in the case of the seed where the 



coats had been punctured (3^0 per cent.), and that this again 



was less than with seeds bared of their coverings (4*0 to 4*5 



per cent.), thus clearly indicating a progressive increase in the 



