1905] MOORE—SPOROGENESIS IN PALLAVICINIA 83 
mitoses, each with bipolar spindles, by which the chromatin is dis- 
tributed in the usual way within the spore mother cell. Apart 
from the rapidity of the two mitoses and the prominence of a four- 
_ rayed achromatic figure in the prophase of the first, the latter author 
holds that there is no essential difference between the processes of 
sporogenesis in Pallavicinia and in other liverworts and higher plants. 
Davis (4a) further maintains these opinions in his recent review of 
the events of nuclear division within the spore mother cell. 
In view of the unusual character of FARMER’s results and of the 
fact that doubt has been expressed as to the accuracy of his observa- 
tions and their interpretation, I have undertaken an investigation 
of Pallavicinia Lyellii, believing that evidence obtained from the 
study of another species of the same genus would help in clearing 
up the disputed points. Some of my results (15) have already been 
published, and they do not confirm FARMER in his main contention, 
namely, the simultaneous distribution of the chromatin. 
Pallavicinia Lyellii is a cosmopolitan species which I have found 
growing abundantly near Columbia, S. C., and in the vicinity of 
Woods Holl, Mass. The young sporophytes make their appearance 
in the early fall and mature about the first of April. The material 
was fixed in chromo-acetic acid and stained with saffranin and 
gentian violet alone, or in the triple combination of saffranin, gentian 
violet, and orange G. Iron-alum haematoxylin was also used after 
the method of Haidenhain. Upon the whole the last-named stain 
has given the best results. The fibrillar structures are not so well 
brought out by it as by the gentian violet, but the chromosomes are 
much more clearly differentiated. 
The spherical resting nucleus occupies a central position in the 
distinctly four lobed spore mother cell. It enlarges considerably 
Preparatory to division and becomes somewhat angular, extending 
into the lobes of the spore mother cell. At the period of synapsis 
the nucleolus is conspicuous for its size and prominence (fig. 1), 
43 1s also the confused tangle of chromatic threads. The spore 
mother cell is not so deeply lobed as Farmer (8) figures for Palla- 
vicwmia decipiens, and Davis (4) and CHAMBERLAIN (2) for Pellia. 
ARMER did not observe the spirem of Pallavicinia decipiens. 
In P. Lyellié it is exceedingly well-developed, and immediately after 
