HornowAv.—Studies in the New Zealand Hymenophyllaceae. 615 
pinnae plagiotropous, but finally the pee - so as to bring the whole 
surface of the frond into a horizontal positi : By March, 1904 
[2.е., nine months after the begi of the pate the new fronds 
of the curly leaved form were identical with those of the type." 
It can only be concluded from these apparently conflicting lines of 
evidence that not only are the epiphytic and the terrestrial stations able 
to produce very distinct effects upon the growth-form of this species, but 
also that it is in such a highly plastic condition that it responds quickly 
to smaller changes in the humidity and other growth-conditions than 
attract our observation 
connection with the subject of the vertical distribution of the 
species brief reference must be made to the fact that the general nt 
flora of the forest tree-tops in the Westland lowlands provides a very g 
indication of the nature of the climatic conditions which the six ^ 
epiphytic species of Hymenophyllum are able to endure. I have found that 
throughout ihe lowlands the high epiphytic flora, in addition to this group 
of filmy ferns, is made up almost ‘exclusively of the cnr Dendrobium 
Cunningham, Earina wem ns, E. ucronata, archochilus adversus, 
and Bulbophyllum pygmaeum, АШ зра of Polypodium — viz., 
P. diversifolium, P. Billardieri (= P. australe), and P. grammitidis— 
Cyclophorus serpens, and eT a codd m. Other plants as well 
occur in the tree-tops, such as Lycopodium Billardieri and species of 
Astelia, although these are by no means so frequent as ec above 
mentioned. These all show striking structural features in correspondence 
with the variable conditions of the tree-tops, but such тай аном 
nd those conditions by the adoption of the owth-form and 
by the imbrication of the fronds к It must be added that the above- 
mentioned epiphytic orchids and ferns, &c., in spite of their xerophytic 
characters, tend to adopt the rupestral | habit | in the less wet districts of New 
Zealand, and are more or less absent from the dry southern-beech forests of 
the Eastern Botanical Districts, showing that the tree-top conditions in 
the Westland forests are by no means severe. Miss K. M. (10) 
has described the special xerophytic features in the anatomy of the 
New Zealand epiphytic orchids. The етте extract is taken from 
the summary at the end of her paper: “The velamen consists of 
one row of cells in Bulbophyllum pygmaeum ae and two or three 
e num 
thickened water-storage (€ are present in the cortex of the root of 
Sarchochilus adversus ; they are also to be seen, though less frequently, 
in the two species of Bar rina . The leaves of Bulbophyllum are 
succulent . . pseudo- -bulbs are , present (consisting of large spirally- 
marked water-storage cells and sm mall assimilatory cells) . . . The leaf 
of Sarchochilus is very succulent.” The high epiphytic polypodies and 
Asplenium flaccidum are also structurally adapted for this station both 
in the thick fleshy nature of their stems and in the succulent or coriaceous 
character of their fronds. The fronds of Cyclophorus serpens are an extreme 
example of this. They are very thick and fleshy, the palisade water-tissue 
though to a somewhat less extent, the upper surface, being densely clothed 
with a tomentum of closely interlocking stellate hairs. The epiphytic 
