1914] ATWOOD—GERMINATION OF AVENA 387 
poorly and unevenly after harvest, and later to increase in viability 
during succeeding weeks. In the work here described, an attempt 
has been made to determine the factor or factors restricting the 
germination of the wild oat, and to investigate the nature of the 
after-ripening changes taking place in the seed subsequent to 
harvesting. 
II. Historical 
I. GERMINATION STUDIES OF THE GRAMINEAE.—It is supposed 
that the common cultivated oat, Avena sativa, has been derived 
from A. fatwa. Traput (64) holds that A. sterilis and A. fatua 
have given rise to two series of cultivated oats: A. sterilis to those 
of the Mediterranean region, and A. fatua to those of Central 
Europe. Instances are reported for A. sativa of what are thought 
to be reversions toward the parent stock (52, 67). The wild oat 
is specially abundant in the Pacific Coast region, where four vari- 
eties have been reported (20): A. fatua, the true wild oat; A. fatua 
glabrescens, the bastard oat; A. barbata, the slender oat; and A. 
sterilis, the fly oat. The wild oat has been found as far east as 
Illinois, but is not troublesome east of the Mississippi River. It 
is especially abundant in the northern small grain belt. Recently 
CRIDDLE (16) has been investigating the false wild oats of Canada, 
which he believes represent some form of deviation from type which 
affects the seed coat only and leaves the seed unaltered. By the 
word “type” reference is made to the normal tame oats from which 
the false wild oats are supposed to have been derived. Yet he finds 
one of the most conclusive evidences, as to its distinction from 
A. fatua proper, in the greater ease with which the false wild oat 
may be germinated. These false wild oats resemble certain tame 
varieties, and may be due to crossing with A. fatwa, although much 
uncertainty has been expressed as to the common occurrence of 
cross-pollination between A. fatua and A. sativa (67). In 1900 
KInze (42) called attention to the progressive rise in germination 
percentage of A. sativa in the months subsequent to harvest. 
ATTERBERG (3), in his studies of the after-ripening of grain at the 
Swedish station, finds he can notably raise the after-ripening rate 
by drying the seed at higher temperatures. Wounding has also 
