HoLioway.—Studies in the New Zealand Hymenophyllaceae. 613 
Although these three species ike rent show specialization in frond-form 
in the way of extension of the lamina and departure from the strictly 
deltoid form in accordance with the зт бее habit, they have not become 
so thoroughly modified as have’ the thin-stemmed and liri pendulous 
species of Hymenophyllum, or as have, on the other hand, the sm inertes 
species of T'richomanes. Moreover, the extent of specializati on in thes 
three species has not apparently resulted in any great raters of the 
stem vascular system. Nevertheless we might expect to species in 
the family represe nting more nearly still the primitive ick 
Emphasis has been laid upon the fact that the реу ee 
= nere de nd H. bivalve possess the deltoid frond-form which certainly 
e the least modified in the existing fimilis. P Бб6й also has 
howi ©) that the eben vascular anatomy of H. demissum corresponds 
very closely with that of the above-named three species. I would suggest 
that H. issum and H. bivalve give a better idea as to the primitive 
stock of the family Чап does the Н. dilatatum group. If this is so, then 
we may perhaps regard this primitive er as possessing a much-dissected 
form of frond with little extension of lamin 
Boodle (2) found that the stem-structure dt several erect tufted spec 
of Trichomanes differed from that of the H. dilatatum group only in so i fr 
as it showed a solid circular core of metaxylem intermixed with parenchyma, 
instead of a more or less broken xylem cylinder enclosing the ау 
placed protoxylem and parenchyma. Не concluded that with regard to 
the stem-anatomy the upright tufted species are not far removed from 
the H. dilatatum group, and he states that it is doubtful еа they are 
to be regarded as more primitive than the latter or as more specialized. 
The suggestion that these tufted terrestrial species represent € original 
stock most nearly of all, not only in their stem-anatomy but also in their 
growth-form, is one which eee be seriously considered. "The family 
as à whole is much modified in accordance with the function of frond 
absorption or in the way of Менн and such t species as 
T. elongatum and T. strictum show such modification to the least extent 
with respect to their general growth-form and frond-form. It seems 
posee pericu to conclude that their stelar structure will also be little 
on the other hand, we might well expect that the creep- 
uH. dina. vill. бе wae ot оь 4 and consequent less 
dependence upon the root and stem vascular system, and still more the 
species of the epiphytic H. dilatatum group with their much greater powers 
of frond чш Pate would show an appreciable reduction in the amount 
of ке а 
eneralization that, on the whole, the де of Hymenophyllum 
seem to have diverged from the primitive stock in one direction and the 
species of Trichomanes in another, and that this sri stock can still 
be traced in the modern family, is in accordance with what has been set 
forth in this paper with regard to the general biology of the New Zealand 
species. The species of Trichomanes keep nearer the floor and, with the 
exception of T. reniforme, are either much reduced or remain for the most 
rt unmodified, whereas the = of Hymenophyllum nearly all show, 
though in different degrees, a particular type of modification which has 
resulted from the epiphytic pendulous habit. 
With regard to the altitudinal distribution, I have noted that in the 
New Zealand family several pairs of species are found concerning which 
not only the complementary regional distribution of the two members of 
