13. A. byzantina C. Koch, the cultivated red oat, is 
grown in southern Spain, southern Italy, Greece, North 
Africa and Asia Minor (Vavilov, 1926) and in the south- 
ern part of the United States, South America, Australia 
and New Zealand (Stanton, 1958). 
A. byzantina, distinguished from A. sterilis by its non- 
articulate spikelets, has three subspecies: byzantina, nodi- 
pubescens and pseudo-sativa. According to Mal’tsev 
(1929), these are derived from A. sterilis subspecies steri- 
lis, trichophylla and Ludoviciana respectively. Except for 
the non-articulate spikelets, the subspecies of A. byzan- 
tina resemble the subspecies of A. sterilis from which 
they are supposedly derived and may be determined 
accordingly. 
Ssp. byzantina, the one most commonly cultivated, 
has the rare naked prol. denudata (Hausskn.) Malz. Ssp. 
nodipubescens Malz. occurs from Asia Minor to Pal- 
estine, while ssp. pseudo-sativa Tihe//. has been re- 
ported from Switzerland and Uruguay. 
That A. sterilis has contributed to the formation of 
A. byzantina seems logical on the basis of geography and 
on the facts that both species are resistant to heat and 
cold and to many of the ordinary diseases of oats (Coff- 
man, 1946). None of these similarities extends to A. 
Jatua, the only other wild hexaploid oat. For the deri- 
vation of A. byzantina from A. sterilis it requires only 
that the spikelet-articulation of the latter cease to func- 
tion. Vavilov (1950) placed the center of origin of A. 
byzantina in the Near East. 
14. A. fatua L. sens. ampl. excl. form. cult. is a wild 
oat with a vast range across Eurasia from the Atlantic to 
Mongolia. It has been widely introduced into North 
America and is a troublesome weed in the hard spring 
wheat areas of Minnesota, the Dakotas, Montana and 
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