208 



STUDIES IN SEEDS AND FRUITS 



features it comes near the average regime of a leguminous 

 impermeable seed as previously given. 



The difficulty 

 of the seeds 

 of Hura 



crepitans. 



Additional 

 data relating 

 to the 

 swelling 

 ratios of the 

 parts of 

 seeds. 



THE CONVOLVULACEOUS REGIME. 



There are seeds where the shrinking and swelling regime 

 presents special difficulties, as in the case of those of Hura 

 crepitans^ the well-known Sand-box tree, belonging to the 

 Euphorbiaceae. In this instance when the pre-resting seed is 

 fully matured, the seed-coverings have already lost consider- 

 ably in weight, whilst the kernel has just attained its maximum 

 development. We encounter here the same difficulty that we 

 meet with when following the development of certain fruits, 

 such as those of Quercus Robur, Barringtonia speciosa, and Cocos 

 nucifera (Coco-nut), in Chapter XIV. The behaviour of the 

 seed of Hura crepitans is fully dealt with in Note 24 of the 

 Appendix and requires no further mention here, except the 

 remark that, like other seeds with oily kernels, such as those 

 of Ricinus and Anona^ there is much less water lost in the 

 shrinking process and regained in the swelling process than is 

 required by a typical leguminous seed. Evidently oily seeds 

 have a regime of their own. 



We will now utilise the results obtained for the seeds of a 

 considerable number of plants where the swelling phenomena 

 were alone observed, and we shall thus obtain a large accession 

 to our data relating to the swelling ratio of seeds preparing for 

 germination with especial reference to the respective parts 



