A CONTRIBUTION TO THE LIFE HISTORY OF ASTER. 
’ MARIE OPPERMAN. 
(WITH PLATES XIV AND xv) 
MATERIALS AND METHODS. 
Tuts study is based upon an investigation of Aster undulatus, 
A. multiflorus, A. Novi-Belgii, and A. Novae-Angliae. Flowers in 
various stages of development were collected. The buds were 
halved, the smaller heads were cut into thirds, and the larger 
into quarters. The upper portion of the floral envelopes together 
with the inclosed styles and stamens were cut away, great care 
being exercised not to injure the ovules. Two fixing fluids 
were used, Flemming’s chrom-osmo-acetic acid mixture and 
chrom-acetic acid, both giving good results. After dehydration 
the material was brought gradually, through ascending grades, 
into either cedar oil or chloroform before infiltration with the 
paraffin. So far as a study of my material goes, it is a mere 
matter of convenience whether cedar oil or chloroform be used 
in the process of imbedding, as the results obtained by either 
method were equally satisfactory. Sections were cut 10 thick 
and stained ‘in Flemming’s safranin, gentian-violet, and orange 
Combination, or in Heidenhain’s iron-haematoxylin. When 
Flemming’s triple stain was used, it was necessary to allow the 
slides to remain for several hours in the gentian-violet, since this 
stain is rapidly removed during the process of dehydration in 
Aster. It was found advantageous to place the slides in xylol 
before mounting in balsam. With this treatment the sections 
Cleared more quickly, and were therefore ready for study in a 
shorter time than when mounted directly from the bergamot 
oil, 
This investigation was carried on in the Botanical Laboratory 
of Wellesley College, under the direction of Dr. Margaret C. 
Ferguson, to whom I desire to express my gratitude for her 
invaluable counsel and unceasing interest and encouragement. 
aed 353 
