Nuclear Studies on Pellia \ 
BY 
BRADLEY MOORE DAVIS. 
With Plates X and XI. 
T HE Hepaticae present an exceedingly attractive field 
for research to the student of the plant-cell. There is 
much of interest in the special peculiarities exhibited in the 
arrangement and organization of the elements in the sporo- 
genous and vegetative tissues and in the details of mitoses, 
which have many distinctive features. However, to the 
writer’s mind, the Liverworts are most interesting in this 
connexion because they offer the possibility of solving certain 
problems of great importance to our understanding of the 
morphology of the plant-cell, and particularly the conditions 
characteristic of nuclear divisions in -the higher plants, Sper- 
matophytes and Pteridophytes. 
Since 1897 a number of contributions have appeared, 
dealing with karyokinesis in many types from these two 
groups, and considering a variety of tissues both reproductive 
and vegetative 2 . Naturally the most striking results have 
1 Contributions from the Hull Botanical Laboratory, No. 25. 
2 The papers have considered such a variety of forms that a brief list of the 
most important contributions is worth a moment’s notice. Arranged approxi- 
mately in order of publication we have Osterhout (’97) on Equisetum ; Mottier 
[Annals of Botany, Vol. XV. No. LVII. March, 1901.] 
