LIFE HISTORY OF PORELLA PLATYPHYLLA 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 184 
FLORENCE L. MANNING 
(WITH PLATES XV AND XVI) 
There was no definite knowledge of the morphology of Porella 
until CAMPBELL (3) published an account of the life history of P. 
Bolanderi in 1904. Under the name Madotheca, LE1tGEB (7) pub- 
lished a few figures of the apical situation. ENGLER and PRANTL 
(5) barely mention the group to which it belongs, and in their 
classification it receives the name Bellincinia (under the group 
Bellincinioideae). From 1904 to 1908, the literature is bare of any 
mention of Porella, that is, so far as its life history is concerned. 
In 1908, ANDREWs (1) accidentally discovered an abnormal situation 
in the archegonium, finding one with two axial rows, each contain- 
ing the same number of neck canal cells, and each with a ventral 
canal cell and an egg. He reported the fact without drawing any 
conclusion as to its probable meaning. All investigators who have 
worked with Porella agree in regarding it as of high rank among the 
acrogynous Jungermanniales. 
MATERIAL AND METHODS.—The material for the present inves- 
tigation was collected by Dr. W. J. G. LAnp, and some of it had been 
in the laboratory in a dried condition for several years. In order 
to revive it, it was soaked for 24 hours in water at a temperature of 
about 31° C. At the end of this period, it was as fresh as though 
it had never been dried; and the subsequent examination of the 
imbedded material showed that it had suffered no ill effects. This 
ability of liverworts to revive after a long period of desiccation has 
long been known. CAMPBELL (2) experimented with some Call 
fornian liverworts and found them able to recover after having been 
dried for months. No satisfactory explanation of this phenomenon 
has been given. GorBeEt (6) mentions the various devices of leafy 
liverworts for holding water for a long period, such as tubers, water 
sacs, etc., but this does not explain the power of revival after 
desiccation. 
Botanical Gazette, vol. 57] [320 
