MACARONI WHEAT 211 



almost smooth near the base, thus differing from those of T. turgidum, 

 which are usually scabrid throughout their whole length. 



The awns are generally straight and more or less parallel to the sides 

 of the ear, though in some varieties they are divergent and occasionally 

 bent in a sinuous manner near the base ; they are longer than those of 

 any other wheats, varying from n to 23 cm. in length, and are more per- 

 sistent than those of T. turgidum, except in some Indian forms, which 

 lose their awns very readily when dead ripe. 



The grains are usually white, amber, yellow, or red ; the latter, when 

 pale and flinty, are extremely difficult to distinguish from white or amber 

 flinty grains. 



The typical form is somewhat narrow, tapering towards both ends, 

 more or less laterally compressed, with a narrow dorsal ridge, and wanting 

 in plumpness, the shallow furrow usually having tlattish sloping sides ; 

 the cross section is more or less triangular (Figs. 139, 140). 



The endosperm is generally very hard and translucent with a vitreous 

 or flinty fracture ; a few varieties approximating towards T. dicoccum 

 or T. turgidum have opaque mealy grains. 



The embryo is large with an elongated oval scutellum. Measurements 

 of grains taken from the middle of the ear of flinty forms gave the following 

 results : 



Breadth. Thickno*. 



Average . 8-30 3-48 3-61 



Limits 70-9-7 2-8-4-1 3-2-4-25 



Ratio . too 41-9 43-5 



VARIKT1KS OF T. durum, Desf. 



(l) Eart bfurdfd 



1. Glumes white, glabrous ; awns white. 



a. (train white . . . var. Irucurunt, Korn. 



h. (train red . . var. nffinc, Korn. 



2. (tluincs white, glabrous ; awns Mack. 



n. (irain white . . . var. Ifucomtlan, Korn. 



h. (train red . . var. Reichenbachii , Korn. 



3. (ilumes white, pulxrscent ; awns white. 



a. (irain white . . var. I'alrnciae, Korn. 



h. (train red . . . . . var fastuosum, Korn. 



4. Glumes white, pubescent ; awns black. 



a. (train white ..... var. mrliwnf>us, Korn. 



h. (irain red . var. africanum, Korn. 



