160 BRYOLOGY OF NEW ZEALAND. 
some forms of which have the teeth divided to or nearly to the base into two 
filiform crura, while in the more usual case they are only partially and very 
irregularly split. But in Rhacomitrium this character is of the least possible 
int their pos on the peristome of Rhacomitrium heterostichum : 
** Peristomii dent bifidi, aie inaequalibus vel omnino 
liberis, vel iviegeibalees conglutinatis, haud raro fissis, nonnumquam toto 
(tab. 265, 266) can hardly fail to convince even the most inveterate 
“ splitter ” that the form of the ariateahoadeth | is the last character on which 
species can be founded in this group. 
Wilson’s MS. notes in his herbarium sate that he finally arrived at 
practically the same conclusions. He writes: “ There is reason to conclude 
that all the New Zealand specimens pees a barren one in herb. Turner 
from Dickson called Grimmia nigricans, agreeing with Dryptodon rupestris 
from Hermite Island) are different states of one species.” I have not been 
able to find this plant in Turner’s herbarium ; I presume it to be the var. 
rupestre, which appears to me to be the extreme form of the species reached 
under frigid and exposed conditions. 
This var. rupestre is exceedingly rare in New Zealand. Colenso’s plants 
so named in Hooker’s herbarium are forms of R. crispulum merely, lacking 
the distinctive characters, — as they are, of var. rupestre. A single 
sterile plant, however, “ 646 Brywm ater, New Zealand. Dryptodon 
rupestris H, f. & W.,” det. Mitten, is the correct plant, not only having the 
colour and foliation, but the voy also exhibiting the peculiar transverse 
striolations described by Car 
A plant in R. Brown’s babar from Stewart Island, comes very near 
the variety, and perhaps should be included under it. It has a very rigid 
habit, the leaves rigidly erect or erecto-patent, both moist and dry; the 
capsule is reddish, the lid long-beaked, the peristome-teeth while long and 
narrow are scarcely divided, mostly only marked by a narrow pellucid 
median line, along which they scarcely or rarely split ; the basal cell-walls 
are seriately punctulate, but the upper cells have not the transverse striola- 
tions described above ; -and the seta is exceptionally short, shorter in fact 
than the capsule. It is obviously therefore extremely near to the variety. 
R. heterostichum neil is cited ed various authorities from Tasmania 
and New Zealand, but I think under a misapprehension. At any rate, all 
the specimens I have seen so named from either Island belong to 
The southern species differs appreciably from R. heterostichum 
ger.) in general habit, the very frequently yellowish ga (rarely the 
black hue that is so common in the northern plant), &c.; but it is not 
easy to define any marked structural differences. A ria common to all 
the New Zealand specimens I have examined, in a more or less marked | 
degree, and certainly less characteristic of R. heterostichum (though 
occasionally found there), is the structure of the basal angles of the leaf ; 
these are more or less decurrent, and, while most o main 
practically unaltered to the point of insertion, a single row of marginal 
cells is markedly distinct, as they are oe not sinuose, and the lowest 
one or two often considerably en 
I have examined the R. Sain Mont. from Chile, and it is 
certainly, as Mitten suggests, identical with R. crispulum. I have not seen 
