POTTIACEAE. 127 
The history of Knight’s plant is somewhat involved. Knight cites 
it as. G. Knightii Schimp. in litt. No specimen occurs in Schimper’s 
herbarium. There is a sheet of “ Weisia Knightii Sch., Nova Zeslacastia’ 
165, Knight & Hutton; mist. 1867.” This, however, is ‘by no means the 
plant under consideration—though quite probably intended to be referred 
to that by Schimper: it is the gymnostomous form of Weisia viridula. 
In Hampe’s herbarium, on the other hand, there is a rt of Knight’s 
actual plant, probably the original, as «“ Gymnostomum Kn ightit_n. sp., 
No. 47, New Zealand,” the generic name and the nu ake Das: in Schimper’s 
hand. It would look as though Schimper sent the whole of Knight’s 
plant to Hampe, marked “ Gymnostomu * for his opinion, ~~ 
that the MS. name Knightii really originated with the latter, and w 
transmitted to Knight y Schiniper. ampe, it would seem, sent oak 
of the specimen to C. Miiller as “ Trichostomum Knightii,’ for C. Miiller 
(Gen. M. fice 3 p. 45) writes, under Trichostomum, § Anacalypta, “ Eine 
nacktmiind ige Art ist Tr. Kn ightti Hpe. von Neuseeland, * 1 think un- 
doubtedly referring to the specimen in question, as C. Miiller’s afar te 
would apply well enough, and = is no other Tr. Knightii to 
in Hampe’s herbarium. It is rather curious that none of the eo 
authors concerned in it observed the peristome, 
4. Didymodon calycinus Dixon in Bull. Torr. Bot. Club, vol. 42, p. 95, 
- t. 9 (1915). 
A very marked species, not only in the long perichaetium, but in the 
quadrate, larger, 8-10 (in W. Weym outhii irregularly rounded, 
e peristome is dark brown, the sixteen teeth divided panes into 
two filiform, scarcely artic ulate, minutely papillose crura, and unite 
base into a well-developed closely and strongly articulate basal membrane. 
e original locality, Mount Bruce, Wairarapa (coll. W. Gray), is the | 
only known station. 
EXCLUDED SPECIES, 
D. papillatus H. £. & W. = gegen 
D. interruptus Mitt = Leptodont 
Barsuta Hedw. 
Distinguished from Tortella by the leaf-margin usually reflexed, and 
by a habit and leaf-structure usually easily recognizable but difficult to 
define ; from Didymodon and the remaining genera of Trichostomeae by 
the entire leaves and usually long, red, twisted peristome ; from Tortula 
by the usually smaller capsules, the narrower, often tineadInesplate leaves 
with small upper cells, and generally smaller and narrower basal ones. 
‘eal TO THE SPECIES. 
1. Soret strongly re ie Sa ae ae othe se 
_°? | Leaf-maryin plane or shehtty § seceriéa ; 2 
(ese, narrow-linear-lanceolate, narrow at ins: basal cells shonisates thin- 
l. au wae 
leans rather widely pines nceolate, » obtusely pointed, basal cells ise 
a differentiated 3. rostrata. 
