220 THE EMBRYO AND COTYLEDONS. 



Gaertner to be remarkably simple, consisting of an 

 uniform medullary substance, inclosed in its appro- 

 priate bark or skin. Vessels are formed as soon as 

 the vital principle is excited to action, and parts are 

 then developed which seemed not previously to exist, 

 just as in the egg of a bird. In position, the Embryo 

 is, with respect to the base of the whole flower or 

 fruit, either erect, as in the Dandelion and other com- 

 pound flowers, reversed as in the Umbelliferous tribe, 

 or horizontal as in the Date Palm,/! \99i^^Gcertner^ 

 t. 9- In situation it is most commonly within the 

 substance of the seed, and either central as in Um- 

 belliferous plants, or excentric, out of the centre, as 

 in Coffee ; in Grasses however it is external. Its 

 direction is either straight, curved, or even spiral, in 

 various instances. The Embryo of seeds that have a 

 single cotyledon, or none at all, is peculiarly simple, 

 without any notch or lobe, and is named by Gaertner 

 Embryo monocotyledoncus . 



Cotylcdoncs-, the Cotyledons, or Seed-lobes, are 

 immediately attached to the Embryo, of which they 

 form, properly speaking, a part. They are com- 

 monly two in number, f. 7; but in Pimis, and Dom- 

 beya, the Norfolk Island Pine, they are more,/! 3, as 

 already mentioned, /;. 7o. When the seed has suffi- 

 ciently established its root, these generally rise out of 

 the ground, and become a kind of leaves. Such is 

 the true idea of the organs in question ; but the same 



