HORDED 



241 



Triticum sestivum'L. (T. vulgare Vill.; T. sativum Lam.). (Fig. 

 60). Wheat. Annual; culms tufted, erect, smooth or pubescent at 

 the nodes, 2 to 3 feet high; sheaths smooth or slightly scabrous, or 

 the lowermost pubescent; ligule membranaceous, about 1 mm. 

 long; blades flat, about ]/% inch wide, more or less scabrous on the 

 upper surface, the base extended on either side into points or auri- 

 cles, these, at least in the young leaves, 

 ciliate; spike dense, more or less 4-sided, 

 1 to 4 inches long; spikelets overlap- 

 ping, single at the nodes, in 2 rows 

 alternating on the zigzag continuous 

 rachis, usually 3- to 5-flowered, ovate, 

 somewhat compressed; glumes coria- 

 ceous, shorter than the spikelets, un- 

 symmetrical or 1-sided, the outer side 

 being broader, arid bearing an obtuse 

 or rounded shoulder or tooth, the sharp 

 keel ending in a point or awn; lemmas 

 similar to the glumes but nearly sym- 

 metrical, more or less 3-toothed, the 

 central tooth sometimes extending into 

 a long awn or beard. This includes all 

 the forms that are grown in America 

 under the name of wheat. There are 

 numerous varieties differing in length 

 of awn, color of the head and of the 

 grain, in pubescence of the spikelets, 

 in the shape of the head, and many 

 other characters. The only other species 

 of the genus grown commercially in 

 America is emmer (T . dicoccum 

 Schrank). Durum wheat is considered 

 to be a variety of T. sestivum. 



Two other species are grown to a 

 limited extent in southeastern Europe. 

 These are Polish wheat (T. polonicum L.) in which the glumes are 

 papery in texture and longer than the spikelet; and einkorn (T. 

 monococcum L.) with disarticulating rachis and slender long-awned 

 heads, the lateral tooth of the glumes pointed, the palea split- 



FIG. 60. Triticum sestivum. In- 

 florescence (head), X Yi', spikelet 

 with portion of attached rachis, 

 X2. 



