376 



A TEXTBOOK OF BOTANY [Cn. VIII, 2 



appendage which contains nutritive substances apparently 

 having a functional meaning in connection with dissemi- 

 nation (page 356). 



Seeds show many structural relations 

 with the ovules from which they develop, 

 precisely as do fruits with their ovaries, 

 though it must not be inferred that all 

 such features in seeds and fruits are 

 simple persistences of ovule or ovary 

 characters. It is equally possible that 

 FIG. 271. Ex-albu- some have originated in seeds or fruits 

 minous seed, of Apple ; and wor k e( i back in evolution into ovules 



The embryo, show- and O varies. 



ing clearly the coty- Every seed shows on its coat a tiny 



ledons and hypo coty 1, 



fills completely the pit, sometimes differently colored, which 

 is the P ersistent though now sealed 

 MICROPYLE, or opening through which 



the pollen tube entered the ovule (page 278). This of 



course has no connection with the much larger scar, called 



the HILUM, left where the seed breaks away from its stalk 



(Fig. 272). Where ovules are turned over on their elongated 



stalks, which are grown to the coats (page 



272), the arrangement persists, in the seeds, 



which show a marked ridge, or raphe. The 



position of the chalaza of the ovule often 



is manifest in a marked chalazal angle in 



the seed. FlG - 272 - Seed 



i , , .... of a pansy ; X 5. 



Appendages, when present, whether hairs, Be iow and facing 

 plumes, hooks, or others, are direct out- to the left is the 



. , - . , . , hilum ; at the point 



growths from the seed coat, and have (invisible) is the 

 obvious function in connection with dis- micropyle; along 



.... . . _^. the side on the left 



semination, as already discussed (page 356). i s the raphe; and 

 Outgrowths of the same kind occur often a * , the , top , is the 



. . . . chalazal angle. 



on ovaries which contain only a single seed, 



in which case one can tell only by dissection whether an 



ovary wall is present or not. 



