Pkascum.] 
IV. MUSCI. 
403 
of mustard, consisting of a little ball of leaves surrounding a capsule. Leaves 
few, closely imbricate, two inner the largest, broadly obovate-rotundate, acute 
or acuminate, very concave, quite entire ; nerve excurrent ; apex erect ; mar- 
gins not recurved. Capsule immersed, globose, erect ; fruitstalk very short. 
Calyptra very minute. 
Northern Island : Hawke’s Bay, on the ground, Colenso. (Tasmania.) Allied to the 
British P. muticum. Mitten (Journ. l.inn. Soc. Bot. iv. 71) has pointed out that the figure 
of the calyptra in FI. N. Z. is quite erroneous. It belongs to the subgenus Acaulon , which 
are annual, simple, and have globose immersed capsules with a minute calyptra. 
2. P. (Pleuridium) nervosum. Hook. Muse. Exot. t. 105 ; — Fl. N. 
Z. ii. £8. A minute, creeping, perennial moss; stems short, nearly simple. 
Lower leaves ovate ; upper elliptic-lanceolate, acuminate, entire or denticu- 
late, appressed; nerve stout, excurrent. Fruitstalk very short, straight or 
curved. Capsule immersed or exserted, apiculate. 
Northern Island : Bay of Islands, in clay hills, Colenso, J.B.H. (Australia, South Africa, 
North America). 
4. GYMNOSTOMUM, Hedwig. 
Tufted, usually short, green, monoecious or dioecious mosses, of various 
habits, usually growing on rock or earth. Fruitstalk terminal, slender, rarely 
short. Capsule erect, rarely inclined ; annulus obscure, persistent ; teeth 0. 
Operculum obliquely beaked. Calyptra cucullate. 
For other acrocarpous mosses, without peristome, that might be referred here, see in 
Weissia, Didymodon, Macrom.itriu.rn , Zygodon, Leptostomum, Physcomitrion , and Hed- 
wigia. 
A very large genus, common in temperate countries, rarer in arctic and tropical ; as formerly 
constituted, it contains mosses of very various affinities, which agreed only in wanting the peri- 
stome ; recently, however, it has been restricted to mosses which, but for the above character. 
would be referred to Weissia. 
Leaves linear-lanceolate ; margins flat 1. G. calcareum. 
Leaves oblong-lanceolate ; margins incurved 2. G. tortile. 
1. G. calcareum, Nees and Hornsch. ; — Fl. N. Z. ii. 59. Very 
minute ; stems densely tufted, i - \ in. high, branched, very slender. Leaves 
spreading, linear-lanceolate, rather obtuse, sometimes crisped when dry ; 
margins flat. Fruitstalk very slender, i in. long. Capsule oval-oblong; 
neck short ; mouth red ; operculum conico-subulate, nearly as long as the 
capsule. 
Northern and Middle Islands: Bay of Islands, on clay soil, the form with crisped 
leaves, on lime in walls, J. D. H. ; Nelson, Mantell ; Otago, Hector and Buchanan. 
(Europe, India, and Australia). I follow Mr. Wilson in placing this moss in Gymnostomum, 
on account of the absence of peristome; the European state has 16 equidistant teeth, and is 
Seligeria nalcarea, Br. and Sch. (Wils. Bryol. Brit. 54. t. 15). 
2. G. tortile, Schwregrichen ; — Fl. N. Z. ii. 59. Stems branched, 
•i — \ in. high, pulvinate-caespitose ; branches fastigiate. Leaves crowded, 
spreading, curved upwards, twisted when dry, oblong-lanceolate, rather ob- 
tuse acuminate or apiculate ; margins incurved, quite entire ; nerve thick. 
Capsule ovoid, rather thick ; operculum with a long beak. — Wils. Bryol. 
Brit. 45. t. xxxviii. ; Hymenostomiun, Bridel, Bryol. Europ. 
Northern Island : Bay of Islands, on clay soil, Colenso, J. B. H. ; North Cape, Jol- 
