9G COTYLEDONS. 



a Strong rentrifugal force applied to vegeta- 

 ting seeds will considerably divert the root 

 from this direction outwards, while the stem 

 seems to have a centripetal inclination. 



The young root, if it grew in a soil 

 which afforded no inequality of resistance, 

 would probably in every case be perfectly 

 straight, like the radical fibres of bulbous 

 roots in water ; but as scarcely any soil is so 

 perfectly homogeneous, the root acquires an 

 uneven or zio-zao; figure. It is elongated 

 chiefly at its extremity*, and has always, at 

 that part especially, more or less of a conical 

 or tapering figure. 



When the young root has made some pro- 

 gress, the two lobes, commonly of a hemisphe- 

 rical figure, which compose the chief bulk of 

 the seed, swell and expand, and are raised 

 out of the ground by the ascending stem. 

 These are called the Cotyledons,/. 4. Between 

 them is seated the Emhrijo or germ of the 

 plant, called by Linnaeus Corculum or little 

 heart, in allusion to the heart of the walnut. 



* As may be seen by marking the fibres of Hyacinth 

 roots in water, or the roots of Peas made to vegetate in 

 wei cotton wool. 



