CALYMPERACEAE. 109 
The principal interest of the plant lies in the fact that it probably marks 
the extreme southerly limit of the genus, which is almost entirely a tropical 
and subtropical one, and one which, with Syrrhopodon, has a curious 3 pre- 
Its occurrence in the Kermadecs constitutes its only claim to be reckoned 
some of the smaller, short-leaved species of Trichostomum, but is at once 
known by the greatly and abruptly widened hyaline cells of the base 
(cancellinal cells), which is thereby rendered very white and shining. 
POTTIACEAE. 
The arrangement of this family by Brotherus (in Engler and Prantl, 
Pflanzenfam., Musci) appears to me a clear and natural one. Exclu uding 
Encalypteae, which I incline to think best teaver as a separate family, 
the genera fall into three groups, distinguishable thus 
¢ flower usually on a lateral origami. ie without stomata II. Crnciiporeae. 
¢ flower terminal. Caps La Rb ochy? 
a. 
Leaves oeniie: aitets ar-lanceolate, never broader the 
upper ha Nerve eed as several Deu ter, no Bogan, and 
ell Soria 4 ds. Upper cells small and u sually obscure, 
I. TricHosToMEAE. 
b. kona a usually wi ingulat 2 to spathulate, Nerve with two median 
Deuter, with Be wn ter, and one stereid band. Upper cells usua 
ppe ually 
larger, lowes elongate, usually Eyalins: often lax and wide III. Porrrmas. 
Of these groups, Cinclidoteae is absent from New Zealand. The genera 
under the other two may be grouped as follows :— 
TRICHOSTOMEAE. 
A. Capsule Seep oe ae oe ‘ a Astomum. 
B. Lid — 
. Peri ae wanting. 
- eee attached to and falling with the lid . Hymenostylium. 
eae not aie with the lid. 
margin incurved, mouth of capsule closed by a membrane 
Hymenostomum. 
Leaf-margin plane or recurved, capsule noi closed by a aaathens 
Gymnostomum. 
b. secon present (rarely biieoby~anse in bang 
Tee oth ri ot ce oe short, 
* Leavy de Arse acute pes acu 
“Btettia filiform, leaves in shinee 3 a highly and oneely 
Bagatt entire aquetrella. 
serrulate above ; : ‘plant robust 
Leptodontium 
** Leaves narrow, or, if wider, obtuse at os 
Leaves small, narrow, soft, peris me-teeth small Weisia 
Leaves very rigid, extremely fia nerve very stout, 
Eucladium. 
ane a widely lingulate, obtuse and rearing 
late ; mooth ; capsule large, wide, 
eat At haa empty ; poaeiraicagroerrl (i 1) wide, 
r ium, 
Capsule oblong to cylindrical, leaves recurved ‘at con 
id: 
8. Peristome-teeth long, spirally twisted. 
Leaf-margin plane or Sarat < i. in Tortella, 
Leaf-margin usually recurved .. - rae Barbula. 
