41 6 STUDIES IN SEEDS AND FRUITS 



the same order possesses plants with both albuminous and exalbuminous 

 seeds, and that the rest-period has been imposed on the embryo in 

 very different stages of its development (p. 403). 



(2) The method of measuring the weight of minute embryos is 

 then discussed, and it is shown that even those of Juncus communis^ of 

 which nearly 70,000 go to a grain, are not beyond the reach of the 

 balance (p. 405). 



(3) The author then gives his results for the weight of embryos in 

 the case of more than fifty kinds of plants, of which nearly a third 

 belong to palms. The only weight-ratio of the embryo that is given 

 is its proportional weight as a part of the kernel, though in the case of 

 ordinary seeds data for estimating other ratios are added. It is con- 

 sidered that the embryo-kernel ratio is the only one that is generally 

 applicable ; and in the table the results are arranged in order, beginning 

 with those seeds where the embryo forms a very small proportion of 

 the albumen and terminating with the exalbuminous seed, where the 

 albumen has all been appropriated by the embryo (p. 408). 



(4) The embryos of palms are specially dealt with, and though 

 the subject has many difficulties, some broad results follow from the 

 author's observations. In the first case it is shown that as^ a rule the 

 embryo shrinks in the drying fruit about twice as much as the albumen, 

 and that in consequence its proportional weight with regard to the 

 kernel is much less in the dry than in the moist fruit (p. 410), 



(5) Then stress is laid on the fact that this great shrinkage of the 

 embryo in the drying fruit usually occurs in the first few weeks or 

 months, and that for this reason the seeds of palms could scarcely 

 be expected to retain their vitality for a long period. Facts are 

 given which show that although the period may be as little as two 

 or three weeks, it does not generally exceed six months. On account 

 of rapid drying being favoured by their peculiar structure, it is con- 

 sidered that ruminate seeds of palms would possess the least staying 

 power (p. 412). 



(6) Allusion is made in passing to the fact that the coco-nut is not 

 peculiar in possessing in the unripe condition a large cavity filled with 

 water, the fruits of other genera of the same tribe of palms being thus 

 characterised, even in cases where they are only an inch in size when 

 full-grown (p. 414). 



(7) The author concludes with the remark that he has approached 

 the subject of the weight and size of embryos mainly as preliminary to 

 the discussion of the rest-period in the next chapter. 



