KEY TU |THE GENERA AND SPECIES OF BRITISH MOSSES, 85 
13 tL S. distichous, oe - : vertical rows on the stem 14 
Ls, inserted in several r 16 
14 {x Ss. V. narrow, nr eeaeie e Distichium 
Ls. param lanceolate or ovate-lanceolate 15 
1 3{ 78 nerved, with sheathing lamina at base Fissidens 
Ls aa a without sheathing lamina. ................00+0 Schistostega 
16 Te. Ls. aca sah 2-nerved), in some cases rudimentary only ......... 17 
21 
17{ 5 alm. teen Is. ig and minute, round base of seta ............ 18 
St. long ; ls. numero 20. 
18 | pebe- auny peristome sod SOOO ONY si icicives ccscckstucen Tetrodontium 
Caps. in clined ; _— of more than 4 teeth 19 
19 | pers. subglobose, cernuous; peristome single Discelium 
Caps gibbous, flattens d above; seribcins “double ......... Burbaumia 
20 { Ls. spongy, whitish, of more a one layer of cells ...... Leucobryum 
Ls. not spongy, of one layer on 175 
Nerve veshnan — Ere on inner face; perist. t. connected ~S : 
s. long. 
21 ac haw mel ‘peviet "absent or rudimentary ; igs WV: st 
ea cone: air 
(nw - Without emily cial. wig ae sitll SYMPANGM 4o.0.5...00600. Pod 
29 \Nerve w. about 3—12 lamelle; calyptra —— naked 23 
v. broad, m uch lamellated; eal. v. hai 24 
23 {7 saigobe te lamelle about 3—6, stra Atrichum 
Ls. not bor. = aga about fer ap sinuous......... Dligoieievu 
> caprle e wine a or Pe iok: not angled ....... en ener we makian 
val; seta short; lid-cells in vertical lines ...... seveereeeeesPottia 
254C Cape "ey lindrie, on longer seta; cells of lid arranged in spiral 
Barbula lamellata 
* 
26 | Ls. with white hyaline points 27 
Ls. lisse hyaline points (or whole leaf colourless) 32 
27 { Ls. m. or 1. tapering to hyaline points 28 
Ls. abieae or spathul. usu. obtuse, n. excurrent ina hair ............ 31 
28 {Re over 4 of leaf near base; Is. m. or 1. subul........ picdads Campylopus 
erve narrow ; ls. m. or 1. ‘ovate or lanceolate 
29 er cells of ls. v. long and narrow, v. nodu .. Racomitrium 
Basal cells not nodulose (or sometimes sinuous operas 30 
30 roe double; caps. immersed, — waves age wo ae et 
P absent or single; caps. immersed o phed sccciiiek Grimmia 
31 { Peristome absent; plant very ‘iat Pottia 
| Peristome single, ‘twisted; ere usually larger ........+..+.-+...-Barbula 
39 | Plant without fruit 121 
1p nt with fruit 33 
t Sometimes a i.e., flattened against the stem so as to appear as 
if distichous; see No. 
dZ 
