On Pallavicinia decipiens , Mitten. 37 
be united either with Pallavicinia or with Symphyogyna , on 
account of their similarity in the vegetative structure of their 
gametophytes, but which are now separated owing to the 
important differences between their respective sexual organs or 
their sporophytes. In fact, similarity in the vegetative structure 
of the gametophyte, in many of these Hepatic genera at any 
rate, affords but unsafe ground on which to found any views as 
to natural affinities and mutual relationships. The existence 
of parallel developments, as above indicated, is a sufficient 
example of the soundness of this statement. 
Pallavicinia decipiens has been described as occurring on 
the Horton Plains in Ceylon, and I found it abundantly in 
this locality, growing on the muddy banks of a stream at an 
elevation of about 6,200 feet. The specimens from this dis- 
trict, as well as others which I found on the summit of the 
Knuckles (6,000 ft.) further northwards, were comparatively 
stunted forms, though they were fruiting freely. At a lower 
elevation (4,500 ft.) the plant assumes a much more luxuriant 
form, and it is not uncommon at this elevation on the slopes 
of Adam’s Peak, especially on the paths up from Maskeliya or 
Ratnapura. Here it grows in large patches and in such pro- 
fusion as to take complete possession of the soil, to the 
exclusion of other plants. 
Branching . — The plant consists, as has been already said, of 
an underground stem, and an aerial part consisting of fronds. 
The latter are formed simply as the ends of rhizome-branches, 
which, after growing horizontally in the earth for a time, bend 
upwards, and after emerging from the ground at once begin 
to flatten out, and branch in such a way as to give rise to 
the appearances of dichotomously branched fronds (PL VI, 
Fig. 1). At the outer side of the angle made by this upward 
curving of the underground stem, one or more rhizome- 
branches are given off, which penetrate the soil, and may 
either branch in it or at once turn upwards, and in their turn 
form fresh aerial fronds. But whatever the ultimate fate of the 
branches, they always arise exogenously throughout the plant. 
In the aerial portions the branching which results in the 
