A Classification of the Varieties of Cultivated Oats 91 
CC. Grains very yellow. 
D. Grains yellow, small, slightly bent; lips of the scar at base of grain 
slightly unequal. 
DD. Similar to D, except that the base of the grain is straight and small, 
with a scar the lips of which are unequal. The plant is further 
distinguished by the form of its panicle. 
II. Grains black, red, or gray. 
A. Outer grains 14-16 mm. long, rarely awned; awn, if present, fine and straight. 
B. Outer grains small, 14-15 mm. long; 1000 grains weigh 33-38 grams. 
C. Grains small, barley-like, 14 mm. long, usually very black, large and very 
plump, with open points; 1 -grained spikelets not occurring; awn 
absent; rhachilla ciliate; lemma very flat. 
CC. Grains small, more or less slender; 2-grained spikelets predominant; 
1 -grained spikelets few. 
D. Grains medium small, with oblique basal scar having unequal lips; 
grains very plump but variable; lemma very convex; 1 -grained 
spikelets few or not occurring. 
1. Grains black and full ; nerves of lemma obscure; rhachilla slightly 
ciliate; basal hairs silky. 
2. Grains brown; nerves of lemma prominent and more or less 
reddish ; base of the grain smaller than in the preceding form. 
3. Grains iron gray to dark and almost black ; nerves of lemma 
obscure; rhachilla smooth; basal hairs absent. 
DD. Grains black, straight, narrow, with slender and more or less reddish 
points; basal scar small, with equal lips; 1 -grained spikelets 
numerous; awns frequent. 
BB. Outer grains of medium but variable size, yellow-reddish; lemma usually flat 
with its nerves usually prominent; rhachilla short and nail-headed; basal 
scar large, oblique, and with unequal lips; 1-grained spikelets not occur- 
ring; 1000 grains weigh 38-44 grams. 
AA. Outer grains 17-18 mm. long; awn usually present, long and geniculate. 
B. Outer grains large, long, very full, uniform in size; 1000 grains weigh 46-50 
grams. 
C. Grains very black, large and full; awn present; base large, and its scar 
having unequal lips; basal hairs present, silky. 
CC. Grains gray or gray-blackish, large and full, with smaller proportion of 
awned grains than in preceding group; nerves of lemma usually 
prominent; basal hairs absent. 
BB. Grains long and thin, not uniform in size; 1000 grains weigh 43-46 grams. 
C. Grains black, slender, very often awned; palea slightly open or pointed; 
rhachilla stout, ciliate; basal scar large, with unequal lips. 
CC. Grains gray and more or less dark, very slender, very pointed, and rather 
often awned; nerves of lemma usually prominent; base of the grain 
and basal scar of medium size; basal hairs present' in a thick ring. 
In the exclusive use of grain characters for the identification of varieties, 
Denaiffe and Sirodot frequently make their characterizations of sections 
so minute and elaborate as to greatly lessen the practical usefulness of 
their system. Another fault is the prominent use of absolute measure- 
ments and weights and of the terms plump, slender, duckbill, and barley-like 
for the description of grains. Such terms have not sufficient meaning to 
