Io BOTANICAL GAZETTE [JULY 
Only one set of experiments was carried out on Rumex, because 
it was found that even immediately after harvesting the seeds 
would germinate. In many of the seeds the coats were ruptured 
and the hypocotyls emerging by the end of the experiment. Cheno- 
podium also exhibited a marked readiness to germinate. Amaran- 
thus was more dormant, but even within a few weeks of harvesting, 
on removing the seeds from the respirometer after an experiment, 
an occasional seed with coat broken was found; while during the 
later experiments, over 100 days after harvesting, the number 
“with broken coats increased greatly (80 seeds per 1000). The 
TABLE IV 
RESPIRATORY VALUES (AT 25° C.) 
Mg. Mg. O: per 
No. of 
Sanit exits | COVO» eben et tn urs tem. 
Amaranthus retroflexus. . ay 0.856 2.691 2.324 
Che di ry ea! 14 0.928 4.213 3.307 
umes crise. | 9 1.160 3.636 2.201 
Cra "BIN Weegee lis Sir 56 0.774 1.548 1.474 
Siinecay eee owes 14 0.675 1.881 2.033 
As wie eee ea eee 30 0.648 2.106 2.392 
Cer te heer. 19 0.866 2.589 2.186 
Senda Cnn 3 ge eee Daan ai al 19 0.876 2.288 T.935 
Blue gage plum........... 19 0.6096 2.579 2.748 
Burbank plum............ 10 0.912 1.998 1.610 
rosaceous seeds are really dormant. Crataegus requires three 
months of after-ripening at low temperature (5° C. optimum) before 
the hypocotyl emerges from the coat. The changes occurring dur- 
ing after-ripening in Crataegus progress slowly (19) until very near 
the end of dormancy. The data reported represent determinations 
covering the period from the first to the seventy-seventh day under 
germinating conditions. At this latter time the seeds are still 
dormant and would fail to germinate if removed to a higher tem- 
perature. For the other rosaceous seeds no attempt was made to 
determine the exact duration of dormancy, although it was observed 
that seeds left in the refrigerator germinated in from 1.5 to 3 
months. 
It has been suggested (17) that the dormancy of Crataegus, 
although chiefly conditioned by the embryo, is in part dependent 
