SIZE OF SEEDS 



59 



some time independent of any fresh supply. In such cases 

 the seedlings sometimes push up for awhile without any fully- 

 developed leaves, the first few being reduced to very small size 

 or almost obsolete, as in Ehus (fig. 44), Sapindus (fig. 43), 

 Tropaeolum, Bertholletia, Camellia, Xanthochymus, Calo- 

 phyllum, Calodendron, Ochna, Citrus, Corylus, &c. 



SIZE OF EMBRYO. 



As already mentioned, there are many cases, in fact many 

 whole orders, in which the ripe seed is entirely occupied by 

 the embryo ; in other cases, again, as in Delphinium (fig. 104), 

 the embryo is very small, and examples of every intermediate 

 stage might be given. 



FIG. 104. Longitudinal and transverse sections of seed 

 of Delphinium Staphysagria, x 12. 



Where it is an advantage to the plant that germination 

 should be rapid, this of course can be more readily secured if 

 the embryo is large. In fact, we find that species with large 

 embryos, such, for instance, as Cabbage, Pea, &c., germi- 

 nate much more rapidly than those, such as Umbellifers, 

 Kanunculaceae, &c., in which the embryos are small. 



On the other hand, in some cases, time is less important, 

 and here other considerations come into play. The protection 

 of the embryo is mainly effected by the outer coverings ; but 



