and its derivatives in subsection Biformes and A. fatua 
with its derivatives in subsection Conformes. Similarly 
Mal’tsev divided the hexaploid oats into two indepen- 
dent species: A. fatua sens. ampl. and A. sterilis sens. 
ampl. Coffman (1946), however, is convinced that all 
hexaploid oats are derived monophyletically from A. 
sterilis, and regards A. fatua as an aberrant weed. It must 
be remembered, however, that it is the cultivated oats, 
with their lack of floret-articulation, which are ‘‘aber- 
rant.”’ A. fatua, although a weed, is a perfectly normal 
self-propagating grass. 
15. A.sativa L.,the common cultivated oat, is widely 
grown throughout northern Eurasia and in the northern 
United States and Canada. According to Stanton (1958), 
it is the most important cultivated oat. 
A. sativa may be divided into four subspecies: macran- 
tha, nodipilosa, sativa and praegravis, derived according 
to Mal’tsev (1929), from subspecies meridionalis, septen- 
trionalis, fatua and cultiformis of A. fatua respectively. 
Kxxcept for the non-articulate florets, the subspecies of 
A. sativa resemble the subspecies of 4. fatua from which 
they are supposedly derived and may thus be determined. 
Ssp. macrantha (Hack.) Ma/lz. occurs as a weed in 
grain fields over much of the same range as A. fatua 
ssp. meridionalis. It has the rare naked prol. nudata Malz. 
Ssp. nodipilosa Malz. is cultivated principally in 
northern Russia, the Ural region, Siberia and Mongolia. 
It has the naked prol. decorticata Malz. which is culti- 
vated in Mongolia and northern China. 
Ssp. Sativa is the most commonly cultivated oat. It 
has the naked prol. chinensis (Fisch. ) Malz. which is some- 
times grown in Europe and North America. 
Ssp. praegravis (Avrause) Malz. is cultivated prin- 
cipally in southern Russia, Europe and North America. 
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