490 Farmer . — On Spore- Formation and 
plant differ considerably from those exhibited in the Junger- 
mannia series. The spore-mother-cell is a flattened oval body, 
rather like a biscuit in shape. The nucleus is prominent and 
large and is enclosed in a coarsely granular protoplasm, from 
which it is separated by a very well-marked membrane. The 
spore-mother-cells increase very greatly in size between the 
last archesporial division and the two final mitoses which 
result in the formation of the spores. As the time for these 
last divisions approaches, the character of the protoplasm 
alters ; it evinces a much greater readiness to take up stains, 
and is more difficult to fix than at other times. But the 
latter remark does not apply to the nucleus, which in this 
particular plant is easy to fix, and gives very clear preparations, 
even at this, the most critical and usually most difficult period. 
It is a noteworthy fact that neither in this plant, nor in any 
member of the Marchantia or Riccia series which I examined, 
was a quadripolar spindle at any time observed k I think that 
this point is of some interest when taken in connexion with 
other differences which exist between these groups and that 
of the Jungermannia alliance. In all of the former sections 
(with perhaps one exception), the absence of the lobed character 
of the spore-mother-cell was noticed, and this is very marked 
when one bears in mind the frequency, perhaps the univer- 
sality, of this peculiarity in the Jungermannia series. It is 
true that the flattened character of the spore-mother- cell, 
which is so striking a feature in Fegatella , is absent from other 
forms, such as M archantia (two species examined), Plagio - 
chasma , Fimbriaria , Riella , Riccia , and Targionia , in which the 
spore-mother-cells are spherical. The last-mentioned plant 
is of interest inasmuch as its spore-mother-cells are at first 
slightly four-lobed, and there is some doubt as to its agree- 
ment with the rest in the main features of its cell-division. 
Unfortunately, however, its protoplasm is excessively difficult 
to fix properly, on account, probably, of the large quantity of 
oil-drops which it contains. Thus, although I had a con- 
1 With the possible exception of Targionia , reckoning it with the Marchanti- 
aceae. See infra , p. 499. 
