284 BOTANICAL GAZETTE [OCTOBER 
of the rupture makes no difference so long as the embryo is not 
injured. 
Nosse and HANLEIN make no mention of the temperature main- 
tained in the course of their experiments and seem unconscious of 
the fact that the temperature plays an important part. Judging from 
the results in Table VIII as compared with their results in Table I, 
they must have run their germinators at relatively low temperatures. 
These investigators, as well as WINKLER, were likewise entirely 
unaware of the effect of the seed coats upon germination. 
6. AVENA FATUA., 
Avena jatua has some germinative characters which are inter- 
esting and which show that the seed coat characters just described 
for other seeds appear in the grasses. Table IX shows that at 18-22”, 
8 per cent. grow with seed coats entire and 96 per cent. with coats 
broken. At 33°, 50-60 per cent. grow with coats entire and 97 per 
cent. with the coats broken. This seed coat character probably dis- 
tributes the germination of a given crop over a period of years. It 
probably accounts for the claim of farmers that these grains will lie in 
pastures and meadows for twelve to fifteen years and then grow 
abundantly when land is plowed. WaALpRoN (12) believes this idea 
is wrong, but it is easy to see how his vitality tests might be entirely 
misleading, for the seed coat character just described was not taken 
- into account. 
7. HAWTHORNS. 
I found, as. is popularly believed, that no hawthorn seeds will 
grow immediately after ripening. The seeds of various species were 
tested by removal of seed coats and subjection to high temperatures 
and high oxygen pressures; but none of these conditions sufficed to 
cause germination. Seeds that lay in the soil for a year or more 
germinated to some extent; while seeds stored in the dry for a similar 
period did not germinate at all, although the tests were made with 
naked embryos as well as with seeds bearing the coats. It is evi- 
dent, therefore, that the change that must precede germination is 
in the embryo itself rather than in the seed coat; but it is also more OF 
less a matter of disintegration, as is true in seeds whose germination 
is delayed by seed coats. 
