INTRODUCTION 3 



generally for each plant few in number and well 

 protected, so that in the struggle for existence they 

 may survive. In the case of small seeds large 

 numbers are produced, and they are not always so 

 well adapted to resist the agencies that exist to render 

 them useless in the perpetuating of the race, such as 

 birds that are seed-eaters, etc. The embryo itself 

 may be large or small. Where it is large germina- 

 tion is usually accelerated. 



In exalbuminous seeds, those without endosperm, 

 the cotyledons have various arrangements which 

 are important in classification. They may lie parallel 

 and rolled up, as in the Sycamore, or they may be 

 doubled, as in the Radish, or be twisted edgeways. 

 They may be divided into 3 lobes or plaited. The 

 radicle may lie turned over the back of the cotyledons 

 when it is incumbent, as in round seeds. If it is 

 turned along the edge of the cotyledons it is accum- 

 bent, as in longer seeds. These arrangements are 

 thus adapted to the form of the seed. 



The embryo has the faces of the cotyledons turned 

 to the placenta as a rule, or the edges may be turned 

 to the placenta. These arrangements are connected 

 with the mode of exit of the cotyledons from the seed. 



The stages of germination are best understood by 

 growing a number of seeds. The seeds can be con- 

 veniently grown in glass beakers or boxes (see Figs. 

 I and 2), the sides of the beaker being lined with 

 blotting-paper and the inside loosely packed with 

 damp moss. The seeds should be soaked for twenty 



