142 



Elementary Botany 



mains of the calyx, whilst the core is the true fruit. This 

 variety is known as a pome. 



In the acheue (fig. 280) all three layers of the fruit are dry ; 

 whilst if they are lignified, as in the Nut and Acorn (fig. 281), 

 the term glans is employed. 



Sometimes we have several fruits produced from the ripening 

 of the apocarpous pistil of a single flower, and the name of 

 etaerio is applied. 



I. II. 



Fig. 282. — Fruit of Dewberry 

 {.Rubits ccesius). I. Natural size. 

 11. A single drupel. 



Fig. 283. — Pseudocarp 

 of the Strawberry. 



Fig. 284.— Section of 

 fruit of Rose. 



Thus in the Raspberry, Blackberry, and Dewberry (fig. 282) 

 we have an etaerio of drupes. In the Buttercup and Straw- 

 berry we have an etaerio of achenes (in the latter case, as we 

 have seen, the edible portion is the enlarged thalamus). 



In the Rose (fig. 284) we have an etaerio of achenes con- 

 tained within a hollow receptacle, and the whole pseudocarp is 

 called a cynarrhodum. 



THE SEED. 



We have already, in Chapter II., described the seed in a 

 general manner ; there are, however, a few details which it is 

 necessary to note at this point. Various terms are used to 

 describe the arrangement of the radicle and cotyledons in the 

 embryo. AVhen the two cotyledons lie flat upon one another, 

 and the radicle is placed upon the line which separates them, 

 as is the case with many cruciferous plants (fig. 285), the em- 

 bryo is pleurorhizal. 



"\^'hen the cotyledons are flat upon one another, but the 

 radicle is placed upon the back of one of them (fig. 286), the 

 embryo is notorhizal. 



