A NGIOSPERMS. — DICO TYLEDONS. 



449 



Thick fleshy cotyledons usually remain in the seed during germination, and perish 

 when all their food-material has been withdrawn from them, as in Phaseoliis mulii- 

 floriis, Vicia Faba (Fig. 376), and Que reus (Fig. 379) ; in this case the stalks of the 

 cotyledons elongate so much, that the plumule between them is pushed out of the seed 

 (Fig- 379) and then grows erect, so that the seed-coat with the cotyledons looks like a 

 lateral appendage of the axis of the embryo. But usually the cotyledons, especially if 



V\G. 379. Qucrcus lobur. I longitudinal section of the embryo mag 

 nified, after removal of the anterior half of both cotyledons c c\ the hypo- 

 cotyl he, the primary root w and tlie plumule b are enclosed between the 

 basal portions of the thick cotyledons, st stalk of the cotyledons. // com 

 inencement of germination ; the pericarp and one cotyledon have been re- 

 moved, and the hypocotyl and the root have lengthened (natural size), 

 /// germination in a more advanced stage after the plumule * has issued from 

 the seed-coat sh and the pericarp j- by the elongation of the stalks of thi 

 cotyledons ; w' its secondary roots- The letters in // and /// as in /. 



l-Iij. 380. Almond germinating: one of the 

 cotyledons c' d dividing ; the letters as in figure 

 379 ; i the first internode very strongly developed. 



they are thin, are destined to further development and form the first foliage-leaves of the 

 plant ; in order to liberate them and the plumule that lies between them from the seed, 

 the hypocotyl lengthens considerably, forming thereby at first a curve convex upwards 

 (Fig. 375), because the cotyledons are still detained in the seed while its lower end is 

 fixed in the ground by the root ; but ultimately a final elongation of its lower portion 

 [2] Gg 



