ee, 
288 BOTANICAL GAZETTE [APRIL 
tion of seeds of hawthorn is due in part to seed coat characters and 
in part to characters of the embryo. With testas removed, in light 
at room temperature, the cotyledons increase greatly in size and 
turn green, but only a small percentage (2-5 per cent) of the 
hypocotyls grow. 
Davis and Rosse (6), working in this laboratory, studied further 
the germination of seeds of Crataegus mollis. They find that under 
ordinary conditions seeds with carpels intact require one year or 
more for germination. Embryos with carpels removed, but with 
testas intact, germinated after 90-96 days at 5-6° C.; 74 per cent 
germinated after 75 days in the cold when removed to the warm 
greenhouse. With both carpels and testas removed, after 28 days 
at 6° C. 78 per cent germinated in 5 days in the greenhouse. Thus 
with all coats removed there is still a delayed germination due to 
characters of the embryo itself, a period of ‘‘after-ripening” 
necessary before elongation of the hypocotyl can take place. It 
has been my purpose to study the changes within the embryo during 
this period. 
Investigation 
I have made a preliminary microchemical study of the chemical 
changes during after-ripening. These results form the basis for a 
quantitative study. This paper gives the results of the micro- 
chemical study, together with quantitative determinations of the 
substances in the embryo at different periods during after-ripening. 
Davis and Rose (6) found the best conditions for after-ripening 
to be a temperature of 5-6° C. This inhibits growth of the 
cotyledons and is favorable for the metabolic changes within 
the hypocotyl. I studied the after-ripening of several species 
Seeds with testas intact were soaked 16 hours at 5° C., were 
washed thoroughly by shaking in a bottle of distilled water (to 
prevent mold), and put in dishes on moist cotton in the ice chest at 
5-6° C. Microchemical tests were made once a week during the 
after-ripening period. Sections were preserved in glycerin for 
comparison. 
