6:34 



PART III.— THE CLASSIFICATION OF PLANTS. 



with the endosperm; during germination the cotyledon absorbs the 

 nutritious matters con- 

 tained in the endo- 

 sperm, while the stem 

 with the other leaves 

 grows out of the seed. 

 Jn other Monocoty- 

 ledons either the coty- 

 ledon is a sheathing 

 scale, or it is the first 

 green leaf differing but 

 little from the foliage- 

 leaves which are sub- 

 sequently developed. 



In many Grasses there is 

 a ecaly ai pendage borne 

 opposite to the scutellum ; 

 this is termed the epiblast, 

 and is sometimes regarded 

 as a rudimentary second 

 cotyledon (Fig. 346 B, I). 



The primary root 

 nsually remains small 

 and inconspicuous : in 

 Grasses generally, the 

 radicle begins to branch 

 before it escapes 

 through the micropyle 

 on germination, so that 

 the root is then fibrous; 

 when this is the case 

 the inadequate root- 

 system is supplemented 

 by the development of 

 adventitious roots in 

 succession at higher 

 and higher levels upon 

 the stem. The epi- 

 blemaof the root is the 

 external layer of the 

 cortex (seep. 154) 



Fig. 345. — Germination of PTicenix dactijlifera, the 

 Date. I. Transverse section of the dormant seed. III., 

 IV. Different stages of germination {IV. the natural 

 si/.e). A Transverse section of the seed at xx in IK. 

 Ji Transverse section of the seedling at x y: C at zz. 

 e The horny endosperm ; s the sheath of the cotyledon ; 

 st its stalk ; c its apex devel >ped into an organ of ab- 

 Borptiou which gradually consumes the endo-'perm and 

 at length occupies its place ; w the primary root; w' 

 secondary roots ; 6' h" the leaves which succeed the 

 cot3 ledon ; (b") becomes the first foliage-leaf, in li and C 

 its folded lamina is seen cut acios?. (After Sachs.) 



