Horrowavy.—Studies in the New Zealand Hymenophyllaceae. 595 
In Westland, however, H. bivalve is much more restricted in its distribution. 
It is not uncommon on the flanks of the ranges in north Westland, and 
even descends to the lowland hills, but 1 have not found it at lower 
altitudes, nor south of the Hokitika River. Throughout New Zealand it 
keeps to hilly forests in preference to those of the lowlands, and is 
undoubtedly an upland plant. These two species are alike in possessin 
fronds. Н. demissum in Westland prefers a sloping well-drained forest-floor, 
and for this reason probably is not so abundant on the flatter wet floor of 
the lowlands as on the lower slopes of the hills and ranges, in which latter 
localities it occurs abundantly in heen open colonies. In places where 
the forest-covering is especially c issum may ascend the trunks 
of large trees and tree-fern stems гн а height of 6-8 ft., but in Westland 
this is an unusual habit with this species. H. bivalve, on the other hand, 
shows a more marked tendency to become a low epiphyte, and this habit 
it preserves in other parts of New rr 
The frond-form in these two reely varies, and even when 
epiphytic they possess the erect habit sida deltoid form of frond- -growth. 
(g.) The Remaining Species. 
It will be convenient to refer to the remaining species individua 
Н. australe (Plate 60) is not found in natural association with any other 
member of the family. It is fairly abundant in the heavy forest of the 
e of Westland and up to an altitude of 500 ft. or 600 ft., but does 
much above 1,000 ft., and at the latter обе i is only to be 
found i in шег humid localities. It occas ionally occurs on mossy rocks, 
but in Westland is typically a low epiphyte on the bases of large trees, up 
which, in very favourable localities, it may ascend to an extreme height 
of 10-12 ft. Like the last two species described, it has a strong creeping 
rhizome with an erect deltoid habit of frond, but it may occasionally si 
found growing most luxuriantly with pendulous fronds as much as 15 іп 
length. Thus, judging from their habit of growthin Westland. the iim 
species Н. demissum, Н. bivalve, and Н. australe, taken in this order, 
present a gadiat progresion in the change from the terrestrial to the 
epiphytic station. A wide Wash character of the frond in H. australe is 
the very broad crisped wing, which extends almost to the base of the stipe. 
Altogether, in both its oak! and its regional distribution, this species 
must be considered more hygrophilous even than such i ee AN 
as H. dilatatum and H. m, which also possess an extended lamina. It 
is of interest to note that H. sanguinoletum may Сола be fo und 
with the same crisped and broad wing-development as is so characteristic 
aust 
: As previously stated, I have not found H. atrovirens (Plate 60) in West- 
land, but since this species is evidently closely allied to H. australe a short 
comparison of the two may appropriately be made here. H. atrovirens has 
a rupestral or low epiphytic plant, and occurs at rather higher altitudes 
than the other species, or ' og stones in gorgy streams,” as Mr. Cheeseman 
informs me. Thus the two species seem to be complementary in their 
distribution. As has already been shown, there are several such pairs of 
species in the New Zealand family. With regard to H. australe, there is 
no doubt that the frond becomes more és when pendulous than it 
is when erect-growing. I have received specimens of H. atrovirens collected 
from mossy gully-walls near Dunedin whose ааа fronds were stated 
t 
