CHAP. III. 
HEPATICJE. 
227 
differences in the number or cohesion of which the generic 
characters of mosses are in a great measure formed. For 
further information upon the peristomium I must refer to 
Brown's remarks upon LyelHa, in the 12th volume of the 
Linnean Transactions. 
The interior of the theca is commonly unilocular ; but in 
some species, especially of Polytrichum, it is separated into 
several cells by dissepiments originating with the columella. 
If at the base of the theca there is a dilatation or swelling 
on one side, this is called a struma ; if it is regularly lengthened 
downwards, as in most of the Splachnums, such an elongation 
is called an apophysis. 
In Andraeaceae the theca is not an urn-like case, but splits 
into four valves, cohering by the operculum and base. 
From the foregoing description, it will be apparent that the 
organs of reproduction of mosses cannot be said to be analo- 
gous to the parts of fertilisation of perfect plants. I must 
not, however, omit the opinion of other botanists upon this 
subject. The office of males has been supposed by Micheli 
to be performed by the paraphyses ; by Linnaeus and Dille- 
nius, by the thecae ; by Palisot de Beauvois, by the sporules ; 
by Hill, by the peristomium ; by Koelreuter, by the calyptra ; 
by Gaertner, by the operculum; and, finally, Hedwig has 
supposed the males to be the staminidia. The female organs 
were thought by Dillenius and Linnaeus to be assemblages of 
staminidia ; by Micheli and Hedwig, the young thecae ; and, 
by Palisot de Beauvois, the columella. 
For some suggestions as to the analogy that is borne 
between the organs of mosses and of other plants, see Mor- 
phology hereafter. 
6. Jungermanniacece and Hepaticce. 
These differ remarkably from each other in the modi- 
fications of their organs of reproduction, while they have a 
striking resemblance in their vegetation. This latter, which 
bears the name of frond or thallus, is either a leafy branched 
tuft, as in mosses, with the cellular tissue particularly large, 
and the leaves frequently furnished with lobes, and appendages 
Q 2 
