AVENE 211 
having the caryopsis loosely and not permanently inclosed in the 
nerved lemma. 
Avena fatua L. (Fig. 44). Wild oats. Differs from A. sativa 
chiefly in the spikelet characters. Florets easily disarticulating, the 
lemma beset with stiff usually brown hairs, 
these more abundant at base, the teeth acute 
as in A. sativa, the dorsal awn well developed, 
over an inch long, geniculate, twisted at base, 
usually brown. A common weed on the 
Pacific coast and occasional elsewhere. 
Avena fatua glabrata 
Peterm. Differs from A. fatwa 
in having nearly or quite gla- 
- brous lemmas. This form can 
be distinguished from the usual 
forms of A. sativa by the 
strong awn and by the easily disarticulating 
spikelets. 
Avena barbata Brot. Differs from A. fatwa in 
having more slender panicle branches and in the 
awned teeth of the lemma. A common weed on 
Fic. 44. Avena the Pacific coast, and a constituent of the wild 
fatua. Spikeletand oats of that region. 
alge Raa Avena sterilis L. Animated oats. Differs from 
A. fatua in having larger spikelets, the glumes nearly 2 inches long, 
and awns about 2 inches long. An occasional weed and some- 
times cultivated as a curiosity, the “seeds’’ moving about as the 
awns twist and untwist. This motion is due to the absorption or 
loss of moisture. 
240. Origin of the cultivated oats—Trabut has shown 
that our cultivated oats are derived from at least three 
wild species. Avena fatua is the parent of most of the 
varieties cultivated in America, and in general the va- 
rieties of temperate and mountain regions. The Algerian 
oat grown in North Africa and Italy is derived from 
Avena sterilis. A few varieties such as Avena strigosa, 
adapted to dry countries, are descended from Avena 
