246 BOTANICAL GAZETTE [OCTOBER 
November 8, 1919, in Parfrey’s Glen near Merrimac, Wisconsin. 
The archegoniophores were removed to prevent the possibility of 
the development of male sporelings from the sporogones, which 
latter were well developed at that time. The plants grew rapidly, 
and apical tips of the plants of the two sexes were fixed at several 
different times during the latter half of December. A few almost 
mature antheridiophores fixed in the field and imbedded in paraffin 
were obtained from Dr. W. N. Stet. In addition to this material 
Dr. ALFRED GUNDERSEN and Professor A. F. BLAKESLEE generously 
supplied living plants from stock received from Copenhagen, and 
Professor A. J. EAmEs sent plants from Cascadilla Ravine, Ithaca, 
New York. Comparative studies were made on these plants, but 
all figures shown were drawn from the Wisconsin material. 
Flemming’s medium solution with 4 per cent of urea added was 
used jn fixing. Paraffin sections 4-6 » thick in the case of the 
apical tips and 3 p thick in the case of the antherids were stained 
with Flemming’s triple combination. The sections on a few slides 
were restained in Heidenhain’s haematoxylin, but gave results 
less satisfactory than those obtained with the triple stain. 
The resting nuclei and stages in the formation of the spirem 
were not examined critically in this study. Numerous nuclei in 
spirem stages and in equatorial plate stages were found in these 
preparations, but very few cases of spirem segmented into chromo- 
somes not yet drawn into the equatorial zone of the spindle were 
seen. Evidently, as observed by Farmer,’ the transition from 
the unsegmented spirem stage to the equatorial plate stage is very 
rapid, if indeed the migration toward the equatorial region does 
not begin before the segmentation of the spirem, as evidenced 
by the frequently observed tendency of the chromosomes to lie end 
to end in the equatorial plate (figs. 2, 3,9). The limited number of 
observations, however, does not justify any conclusion on this point. 
Judging by the large number of nuclei in the equatorial plate 
stage, a considerable pause in the movement of the chromosomes 
occurs at this point, which also coincides with FARMER’s observa- 
tions. The longitudinal splitting of the chromosomes does not 
3 FARMER, J. B., On spore formation and nuclear division in the Hepaticae. Ann. 
Botany 9:469-523. 1895. 
