16 



Botanical Section 



[PT i 



(C) FRUITS ("Seeds "). When the fruit (grain) of a grass ripens 

 the rachis of the spikelet usually breaks up and allows each grain 

 to fall away tightly entrapped between the two paleae (Fig. 19). 

 When the palese are present there is usually a small portion 

 of the axis of the spikelet attached to their base upon which the 



End- 



-Col 



Fig. 20. Median longitudinal section through the lower part of a wheat grain, 

 showing the position and structure of the embryo. End. endosperm, 8c. 

 scutellum in contact with the endosperm by Ep. the epithelial layer. Ap. 

 the growing apex, and Rad. the primary root of the embryo. Sh. the germ- 

 sheath, Col. the root-sheath, Cap. the root-cap, x about 15. 



"seed" immediately above was borne. This is called the rachilla 

 and lies in front of the inner palea at the base of the "seed." 

 This is the usual type of what is commonly called a grass "seed." 

 In some cases however the "seed" consists of the entire spikelets, 

 i.e. of the glumes, palese, and grain of one or more flowers, as in 



