HOOKERIACEAE. 279 
HOOKERIACEAE. 
This large and very interesting Family has widely varying vegeta- 
tive aoe while certain of the fr sbegpis characters are constant 
and s cid this is notably the case with the calyptra, which 
i apaner etrical and mitriform, most fre cate fringed at aw base, 
— often yap or spiculose or even ciliate above. The epider- 
cells of the stem and branches (as in Fabroniaceae eB are 
ally lax Re thin-walled. It is one of the very few Families, also, 
which has frequently a double nerve to the leaf, with two prolong 
branches, sometimes reaching nearly to the apex. Very nearly all the 
genera, som e thirty, are confined to the tropical or subtropical regions 
of the wor 1d. It is represented in New Zealand by six genera, for the 
most part fairly distinct; but it may be helpful to furnish a key to 
the main characters, the large genus Hookeria as formely understood, 
and as used in the “Handbook, ’? having been split up into a number 
of smaller genera 
Key. 
Leaves poodle lee acute or acuminate . ae ng 2 
1 or less ne or rounded, wide 
4 
2 { Nerve 0 tise auth ey pia sae eee eee pe 
erve single, long ea toe Soc aust ree 3 
{ Nerve ceasing below apex Sie use nae Dartonia 
3 Nerve reaching — or excurrent ess dete cows Betta 
Nerve 0 or doubl eee ue wo «=—§ BTIOMUS 
4 { Nerve single, or cari ‘at apex a eA 5 
Nerve undivided, leaves narrowly beirdeiad bom 
5 uding D. microcarpum ..  Distichophyllum 
Nerve often forked at apex, leaves unbordered ..  Pterygophyllum 
Daltonia Hook. & Tayl., Muse. Brit., p. 80 (1818). 
A large and very distinct and homogeneous genus, mostly confined 
to the tropics. In Journ. of Bot., 1914, p. 123, I have pointed out 
that the Handbook of the N.Z. Flora i is in ete: in making D. novae- 
Syie pewe Mitt. a synonym of D. nervosa (H. f. & W.). The tater 3 is 
w placed in the follo ras genus, Bellia, v while D. novae-zelandiae 
is a true Daltonia, and nie a different plant, the affinities of which 
I have discussed in that crite 
The cells in Daltonia : are narrowly oval or elliptical. 
D. novae-zelandiae Mitt. in Journ. Linn., Bot., iv, 95 (1859). 
A small moss, growing on twigs, often among other mosses and 
hepaties, readily known by the Hookeriaceous calyptra, the narrow, 
acuminate leaves, narrowly bordered an eeply eae tai with 
characteristic areolation, and the nerve ceasing fat a the ap 
It appears to be rare, but oceurs in both Islands. 
Bellia Broth. in Engler & Prantl. Pflanzenfam., Musci, ii, 923 ( 1907). 
- This genus, consisting of one exclusively New Zealand species, was 
SNS ae from Daltonia on the ground of the inflorescence, the estri- 
_ate, papillose peristome teeth, ah zigzag median line, and. the 
