COTYLEDONS, 



a strong centrifugal force applied to vegeta- 

 ting seeds will considerably divert the root 

 from this direction outwards, while the stem 

 i.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 zigzag 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. Between 

 them is seated the Embryo 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 

 wet cotton wool. 



