Moore — 0>i the Mosses of Ireland. 
335 
Tribe 4. Leucobrye.!:. 
Pale, whitish, glaucous mosses, growing in dense masses, with dicho- 
tomously branched stems. Leaves soft, pale, white -coloured, con- 
sisting of two or more layers of large pellucid cells, among which 
are intercellular chlorophyllose passages. Fruit terminal from 
the stems or branches ; capsule erect or inclined ; peristome single 
of 16 bifid teeth. 
One genus. .23. Leucobeyum. 
Tribe 5. Trichostomace^. 
Mosses growing in close tufts, gregarious or scattered. Stems usually 
more or less erect, rarely creeping. Leaves spathulate, linear- 
lanceolate or linear- subulate, with nerves, which are sometimes 
excurrent into piliferous denticulated points ; areolation roundish, 
lax or dense, lower cells often large, pellucid, and more linear. 
Fruit terminal, rarely lateral; capsule operculate or solid; 
peristome wanting, or single of 16-32 teeth, often filamentous, 
more or less combined at base, or more or less spirally twisted. 
Genera, 
a Fruit terminal. 
Sect. 1. Phasce(B. 
Operculum persistent, not caducous. 
Calyptra small, conical, split on one side or cu- 
culliform, .24. Phasctjm. 
Calyptra conico-campanulatc, entire, . . 25. Systegium. 
Sect. 2. Weissiece. 
* Peristome none. 
Calyptra cucullate beaked, extending below the 
operculum, 26. GYiiNOSTOMm. 
Calyptra smooth or rough at apex, long persis- 
tent, 27. POTTIA. 
Peristome of 16 single teeth. 
Teeth simple, equidistant lanceolate, . .28. Weissia. 
Sect. 3. Triehostomece. 
Tooth narrow, acicular, rather long, . . 29. Splachnobrycjm:. 
-H^ii-^ Peristome of 16-32 teeth in pairs. 
Teeth without a basilar membrane, . . 30. Didymopon-. 
