MOSSES OF NEW ZEALAND, 447 
leaves curled when dry. From other plants of more similar appearance 
it is distinguished by its gymnostomous capsule and larger papillose cells. 
Macromirrium nETUSUM, Hook. f. & Wils. Waitakarei Hills (Murray, 
No. 26). 
M. capvciriLUM, Lindb. Waitakarei Hills (Murray, No. 264). 
А doubt has often presented itself to my mind as to whether Macromitrium 
caducipilum, Lindb., and M. retusum, Hook. f. & Wils., were distinct species. 
They were described independently, and there is no reference to the former 
in the * Handbook’ description of М. retusum. While that species was 
certainly not known to Lindberg (although his species was not described 
until several years later than the original description of М. retusum), this 
is clear from his deseription of the remarkable deciduous nerve in his species, 
“structura nervi ab omnibus speciebus generis distinctissima et curiosissima," 
which structure is, however, exactly identical in the plant of Hook. f. & Wils. 
Nor is there anything in the descriptions of the two mosses to distinguish 
one from the other. Among Mr. Murray’s gatherings, however, were some 
of а Maeromitrium which I at once referred to М. retusum ; but on closer 
examination at a later time I detected the presence of two distinct plants, 
noticeably differing in the enrolling of the leaves when dry. After careful 
examination [ was able to find other differences; and on comparison with 
original specimens, on the one hand of M. retusum (Colenso, 1911, in herb. 
Wils.), and on the other of M. caducipilum from an original specimen from 
New Zealand leg. Ralfs, kindly lent me by Dr. Brotherus, I was able to 
assure myself of the identity of Mr. Murray s two plants with the two 
species in question. Аз they have not previously been. compared, it will be 
well to indicate shortly the distinguishing characters. The peculiar struc- 
ture of the nerve is deseribed briefly by Lindberg in his diagnosis of the 
species, and at length by Correns, * Vermehrung der Laubmoose,’ p. 121. 
The leaves in M. retusum are more spreading than in M. caducipilum : in 
the latter they are straight and erecto-patent, with no marked differentiation 
of base and lamina : in the former the base is erecto-patent, and the upper 
part is distinctly bent back above the base so as to form a separate, more 
patent lamina; this latter part in M. retusum is of a very marked oblong- 
lingulate form, with the margins entirely straight and parallel up to the 
obtuse apex, while in Lindberg’s plant it i» shorter and usually shows some 
narrowing towards the apex. The nerve in M. retusum is stouter, about 
15-50 р in width near the base, that of J. caducipilum measuring (in the 
few leaves which I have been able to examine) 35-45 ш; and the upper cells 
in M. caducipilum are perhaps а shade larger (5-8 р wide) than in M. retusum 
(5-7 ш wide). The position of the leaves in the dry state affords the best 
test ; the leaves in M. caducipilum are spirally twisted round the stem, with 
