THE WALLFLOWER 



137 



3. 



2. 



or modified integuments, and the embryo. The whole 

 interior of the seed is 

 occupied by the large 

 curved embryo. At the 

 end next the micropyle 

 is the radicle of the em- 

 bryo, and above this is 

 the hypocotyl. At the 

 upper end of the latter 

 the two broad cotyledons 

 are borne, and between 

 them is the plumule, or 

 growing point of the 

 stem (see Fig.49). Many 

 seeds contain a much 

 larger amount of per- 

 manent food tissue, in 

 the form of endosperm 

 within the embryo -sac, 

 to be used during ger- 

 mination, e.g. Buttercup, 

 Fox - gloxe, Castor - oil 

 seed ; while in a few the 

 nucellus is persistent, 



forming the perisperm, FIG. ^9*. Three mature fnute of tho 

 e.g. Pepper, Water-Lily. 



i. The Fruit 



The pistil ripens into 

 the fruit or seed-vessel. 

 In doing so it increases 

 greatly in bulk, growing 

 from a quarter of an inch 

 to two inches or more 

 in length (Fig. 49*, 1). 



Its tissues show changes 



Wallflower, borne on the peduncle. 



1. Fruit still closed, x, x, line of 



transverse section, as shown in 

 Fig. 50. 



2. Fruit dehiscing, v, v, the open 



valves ; r, replum, seen edge- 

 ways, with seeds attached. 



3. Fruit after valves have dropped 



off, seen in plane- of replum, 

 r. s, septum stretched across 

 replum ; sd, seeds, showing pari- 

 etal placentation ; st, stigma, in 

 all three figures. 



of natural size. (R. S.) 



of some interest. Perhaps the most important change 



