236 CHAPTER XIV 



T. durum (Durum or Macaroni Wheats). — Next to com- 

 mon wheat this is the most important group in South Africa 

 and elsewhere. As a class its varieties are among the most 

 drought and rust-resistant of wheats ; they are tali and erect, 

 with smooth, bright green leaves, and long, narrow, translu- 

 cent grain of exceptional hardness, which is invariably rich 

 in gluten, but poor in starch. The heads are usually heavily 

 bearded, and vary in colour from light yellow to a bluish-black. 

 Under dry-land, arid conditions, they are superior to other 

 strains of wheat. Because of the density and high gluten con- 

 tent of the seed, they are well-suited for the manufacture of 

 macaroni. They are used to a certain extent in blending flour 

 to increase the strength. They give, however, a dark 

 coloured flour and bread, which from the consumer's point of 

 view is objectionable. In the United States of America this 

 is overcome by bleaching with nitrogen peroxide. 



T. vulgare (Common Wheats). — This is the chief of the 

 bread wheat groups, Poulard and Club wheats being the two 

 other bread wheats. It is the most grown of all and, probably, 

 about 90 per cent, of the world's wheat belongs to this group. 

 The grain is free, ears awned or awnless, stems hollow, grain 

 white or red. As a class they are high yielders and their 

 period of maturity varies considerably, hence winter and spring 

 wheats in nort.hern countries. Drought and rust-resistant 

 qualities vary with the varieties of the group. 



The types of wheat fall into two natural groups as to 

 attachment of lemma and palet to grain, as follows : — 



(1) Naked Wheats, in which the grain comes free from 

 the lemma and palet, and the rachis is tenacious, e.g., T. 

 durum, turgidnm , compactum, vulgare and polonicum. 



(2) Spelt Wheats, in which the grain remains attached to 

 the lemma and palet, and the rachis is fragile, e.g., T. mono- 

 coccum, dicoceum and Spelta. 



Principal South African Wheats.^ 



I^ate . . . . . . Black Persian . 



Medium to late .. Kubanka, Golden Ball. Bon- 

 Durums . . • • -^ taar, and South Africaa 



Medeah. 

 Early . . . . Blaok Don. 



