390 SIB J. LUBBOCK — PHYTOBTOLOGICAL OBSEBTATIONS. 



Auricled Cotyledons, 



Some cotyledons are niarlcedly auricled. As illustrations I 

 give Fofenum (fig. 42) and Ilakea (fig. 21). This fomn is, I am 

 disposed to suggest, aproyision to fill up vacant space in the seed. 

 In the seed of IlipjjopJiae (fig. 55) the form of the cotyledon 

 leaves at each side of the base of the cotyledon two spaces (^), 



which are occupied by perisperm. In CupTiea (fig. 100), Jhiellid 

 (fig. b1\ ^nUi Poterium (fig. 99), on the other hand, there is no 

 perisperm, and it is consequently an advantage that the cotyledon 

 should develop auricles in order to fill up the space. 



If this is the explanation of the auricles, we should expect to 

 find them developed principally in families Avhere the perisperm 

 is deficient. Kow in the species I have examined, auricled coty- 

 ledons occur in 35 genera, belonging to 22 families, of which 13 

 have no perisperm, while in 6 of the 9 others it is reduced almost 

 to a film. 



The argument in the case oiCuplea is further strengthened by 



the peculiar conformation of the radicle (fig, 100), which is 



three-lobed, the reason being, I would suggest, that the radicle 



cooperates with the cotyledons in the endeavour to fill up the 



vacant spaces. 



Fig. 129. 



Fig. 127. Fig. 128. 



Three stages in the growth of the seedling of Cicphea silenoides. 



In support of tliis view I also would observe that the auricles 

 seem to be of little use to the young plant. For instance, the 

 embryo of CujjJiea, while in the seed (fig. 100), has very large 

 auricle?, which in the seedling (figs. 127-129) soon disappear. Iq 

 Huellia, again (conf. figs. 57 and 16), we have a similar case. 



Size of Seeds . 



As regards the size of seeds, if we could imagine a state of 



