RIVET OR CONE WHEAT 245 



nerved, the portion from the midrib to the outer edge being 4-5 mm. across, 

 the inner membranous part being half as wide. The strong apical tooth in 

 some varieties is acutely pointed, 1-1-5 mm - I n g> anc ^ curved inwards, in 

 others short and blunt. A well-marked keel runs from the base to the 



234567 9 



FIG. 152. Empty glumes of Rivet wheat (7*. turguhtm) ( x 2). 



tip, and a more or less prominent lateral nerve is present on the outer 

 broad half of the glume, running from the base to a point close to the 

 apical tooth, where in some forms it terminates in a short secondary 

 tooth (Fig. 152). 



IOCOOOC (I 



Flu 153. tirajns of Rivet wheat ('/'. tui^idum), front, back, and side views (nat. size). 



The empty plumes of the terminal spikelet are ovate and more or less 

 symmetrical (Fig. 78). 



The flowering glumes are thin, fragile, and pale ; even in the black- 

 eared varieties the dark tint is not developed in the part covered by 

 the empty glume. They are oval, inflated, and boat-shaped, \\ithout a 



