OF THE GRAMINEJE. 589 



a greater or less number of which are subsequent- 

 ly evolved, by the joint agency of the roots and 

 leaves. 



My experiments were made with the seeds of 

 the different species of grain commonly culti- 

 vated * ; but as the result on the whole was simi- 

 lar, those only in which the seeds of Triticum 

 were used shall be stated. 



Soon after a grain of wheat is committed to the 

 damp earth, it swells, becoming more plump and 

 soft. A protuberance appears at the lower part f 

 of the convex side, which, shooting downwards 

 in the direction of the axis of the seed, bursts 

 through the Testa and the under part of the sheath 

 which envelopes the Seminal Germ (/;). This radicle 

 is followed by two others, one on each side \ and 

 at the same time, the first stem, in the form of a 

 small bulb, shoots upwards from the Tuber, which 

 unites it with the scutellum, in the concavity of 

 which it lies previous to the commencement o£ 

 germination. Plate XIII. fig. i. represents these 

 parts a short time after germinating ; the convex 

 back of the scutellum being separated from the 

 farinaceous perisperm in which it was embedded, 

 and from which it absorbs the first aliment of the 

 infant bulbs. Fig. 2. represents the first plant after 



* Hordeum distichum, and hexastichu?n, Avena saliva, 

 Triticum hibernum, 



f The base of a seed is understood to be that part 

 by which it is connected with the receptacle of the ma- 

 ternal plant. 



