534 



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. 

 In 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 scaly appendage 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 

 usually 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- 

 blema of the root is the 

 external layer of the 

 cortex (see p. 154). 



FIG. 345. Germination of Phoenix dactylifera, the 

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

 IF. Different stages of germination (IV, the natural 

 size). A Transverse section of the seed at xx in IF. 

 B Transverse section of the seedling at x y : C at z z. 

 The horny endosperm ; s the sheath of the cotyledon ; 

 st its stalk ; c its apex developed into an organ of ab- 

 sorption which gradually consumes the endosperm and 

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

 secondary roots ; b' b" the leaves which succeed the 

 cotyledon ; (b") becomes the first foliage-leaf, in B and C 

 its folded lamina is seen cut across. (After Sachs.) 



