New and Little Known West-Himalayan Liverworts. 225 
undoubtedly reduced and is admitted as such by all. We can see 
in the species of Cyathodium described above the actual reduction 
of a composite receptacle into a simple disc by the transformation 
of some of the branches into vegetative shoots and the sligh t 
development of the rest so that the margin of the male receptacle 
does not show any lobes. Indeed, according to this view of whole¬ 
sale reduction the guiding principle in the evolution of the living 
Marchantiales has been to increase the amount of vegetative tissue 
at the expense of the sexual organs and the sporophyte. The 
writer has already pointed out that in Mussoorie at least repro¬ 
duction by spores hardly plays any part in the multiplication of the 
species. The great power of reproducing themselves by vegetative 
means possessed by all Hepaticae everywhere indicates that the 
reproduction by spores in these plants is only of a secondary impor¬ 
tance in these days. For this reason the complex receptacles and 
the complex sporophytes are disappearing and have disappeared in 
all probability in ancient times. 
If a male receptacle can he transformed from a composite type 
to a simple type as in Cyathodium tuberosum, and even such a type 
again to a mere cushion on the vegetative shoot which is the case 
in Targionia, surely the female receptacle may undergo the same 
changes, particularly when we find intermediate stages, like the 
receptacle of A itchisoniella, between Targionia and Exormotheca. If in 
Aitchisoniella the shoot which is going to form a female receptacle 
produced at first for some time vegetative tissue, we would have a 
female branch of Targionia type, in which the shoot does not fork 
and there is therefore only one receptacle. But if the shoot forks, 
or two or more shoots close to each other behave similarly, we 
would have a female plant of the type of Cyathodium tuberosum. 
Just as the male receptacle of this species is derived from a composite 
receptacle by reduction, similarly the female shoot of this plant must 
have been derived from a composite receptacle possessing many 
involucres. Thisviewwouldalsoexplain the fan-shaped appearanceof 
the female plants. We know two involucres are often found in the genus 
Aitchisoniella. Thus Targionia and Cyathodium may be compared as 
simple and compound types, while Aitchisoniella is intermediate. It is 
probable, in view of the numerous differences between the two 
former genera, particularly as regards the sporogonium, that they 
have arrived at the same structure as regards the female receptacle 
by parallel evolution. The presence of a composite male receptacle 
in Cyathodium tuberosum along with the facts of the structure of the 
