340 Proceedings of the Royal Irish Academy. 
Tribe 14. Hypne^. 
A yery extensive tribe of mosses, small or robust, with creeping stems, 
irregularly or subpinnately branched. Leaves and other parts 
of the plants very variable, vrhich renders it necessary to divide 
them into sub-tribes, and lesser natural groups. 
Sub-tribe 1. Isothecie^. Capsules mostly erect and symmetrical. 
Genera. 
Leaves spreading or subsecund, not striated ; 
inner peristome 16 short membranous 
processes, slightly adherent to outer teeth, 64. Pterigonium. 
Stems more or less dendroid ; inner peristome 
a membrane cut into 16 carinated pro- 
cesses, with intermediate cilia, . . 65. Isothecitjm. 
Stems dendroid ; inner peristome of 1 6 pro- 
cesses; longer than the teeth, and alter- 
nating with them, .... 65^. Climacium. 
Peristome double; interior of 16 cilia, rising 
from a plicated base, .... 66. Homalothecium. 
Stems creeping ; peristome double ; inner 
cilia rising from a short basilar mem- 
brane, interruptedly cleft along their 
keels, ....... 66"^^. Pylaisia. 
Sub-tribe 2. Thtjyidie-s:. Capsules more or less cernuous. 
Stems dendroid, rhizomatous at their base, . 67. Thamnium. 
Stems prostrate, radiculose, slightly villous ; 
inner peristome with filiform processes 
between each of its segments, . . 67*. Heterocladium. 
Interior peristome consisting of teeth longer 
than those of the outer, irregularly 
divided along their keels, . . .68. Myueella. 
Peristome double ; the exterior teeth trabecu- 
lated ; those of the interior rising from 
a basilar membrane, and as long, or lon- 
ger, than the outer teeth, . . . 68"^ Leskea. 
Leaves yellowish- green ; areolse dense ; inner 
peristome of 16 short fragile processes, 69. Anomodon. 
Stems villous ; leaves papillose ; outer peris- 
tome of 1 6 teeth, confluent at the base ; 
inner of slender truncate cilia, . .69^ Thttxidium. 
Sub-tribe. 3. Camptothecie^. 
Inner peristome a plicate membrane, divided 
halfway into carinate cilia; ciliolae present, 70. Hypnum. 
