440 ALpEN: LIFE HISTORY OF UVULARIA SESSILIFOLIA 
condition, for here the midwinter catkins showed pollen grains 
in which the tube nucleus and generative nucleus were distinct. 
At first thought it would seem that that point which marks the 
end of the sporophyte generation would mark the end of the 
growing season. This has been made a generalization.’ Cham- 
berlain® suggests further that since the mother cell stage appears 
as a common halting place for the winter, this may be the condition 
most capable of withstanding the unfavorableness of winter. 
However, even the few instances given above show enough variety 
to lead one to suspect that perhaps the mother cell stage in winter 
is not to be found in a high enough majority of cases to warrant 
such an interpretation. The particular plant taken for this study, 
Uvularia sessilifolia, is one in which neither microspore nor mega- 
spore passes the winter in that turning point of sporophyte and 
gametophyte phases. 
The study is but a preliminary one and intended largely to 
indicate the time at which the various stages in the life history 
are to be sought. A cytological study of the stages here given 
is in progress. 
COLLECTING AND METHODS 
The buds of the rhizome of Uvularia sessilifolia were taken 
at intervals during the year as given below in detail. In the 
earlier stages the tips of the rhizome were put directly into the 
fixing agent, while in the later material from one to several of 
the bud scales were first removed. In the spring material the 
bud was dissected and the flower alone fixed. The fixing fluid 
used was chrom-acetic acid; time, twenty-four hours. The ma- 
terial was then washed and run through successive grades of 
alcohol, beginning with 15 per cent and changing the final absolute 
alcohol once. The infiltration was with cedar oil, 33 P& cent 
cedar oil and absolute alcohol, 66 per cent cedar oil and absolute 
alcohol, and two changes of pure cedar oil. The paraffin se 
gradually introduced into the cedar oil and the material finally 
imbedded in pure paraffin melting at 54° C. 
cut about 7 mm. thick and mounted serially. 
toxylin was used in staining, as only the general stages we 
Delafield’s hem@ 
re sought: 
