KEY TO THE GENERA AND SPECIES OF BRITISH MOSSES. 901 
PLAGIOTHECIUM. 
1 se. or shortly acuminate, v. complanate, subentire ......... osveveereD 
Ls. w. tapering acumen, smaller, often less regularly complan. . sate 4 
9 trea ——— undulate, pale, bluntish; pl. robust ...... un —— 
Ls. 
3 > is green, glossy when dry; lid conic...........0++0+ dontioulaltun 
Ls. darker, opaque when dry; lid w. long beak..........000+ sylvaticum 
af decurrent on the ste 
Ls. not decurrent 6 
5 = v. small; ls. laxly saarse ee entire ; a smooth ...... latebricola 
. usu. secund, w w. serrul. acumen; caps. striated ...... Mihlenbeckw 
{te cae pointing upwards, w. long, s shee ACTUMEN...++- silesiacum 
6 8 up 
Ls. not curved u as rds, complan. or apes aas secund ...... otedesbiad 
fi senkaa complan., glossy, Ww. rs: — dioicous .........8 
7 
Ls. narrower, laxly co complan., aes aia 9 
8 Ls. ne to narrow, ampere tothed acuMeN...... Borrerianum 
Ls. acute acumin . above ...... Blapan cost. pisomcoe 
9 ee ee panes often bsieiv- oa pres be vig tcciivese pulchellum 
Ls. ec subseeund, more shining; CAPS. CELNMOUS «eeeeeess nitidulum 
PLEURIDIUM. 
{ Perich. ls. similar to others; n. narrow; cells r. lax ..........+. nitidum 
1 Perich. Is. much onan than others; n. strong; oa small 2 
Per. ls. lanceol.-subul., w. antheridia naked in axils ......... subulatum 
24 Perich. ls. from a broader base, suddenly subulate- peregrine barren 
flower gemmiform, axillary 
POGONATUM. 
{ef . short; Is. broadly lanc., dull green, ——— at margin.........2 
St. longer, usu. branched; Is. narrow-lan WG TIGIG sce ssansoe ge ensD 
Tr obtusely ee caps. subglobose; coheed eylindric ... 
L arply serr.; caps. cylindric; columella 4 -winged .....-+.. pin nto 
3 { Caps. een. erect; Is. usu. reddish-brown below ...wrnigerum 
(Caps. oblong, tumid, inclined; st. usu. much branched wees alpinum 
POLYTRICHUM 
1 Ls. eee margin inflexed 2 
Ls. sha iat serrate, acuminate, margin plane 5 
9 { Ls. m, or |. obtuse at apex, — igh sexangulare 
21 Ls. sicseia at apex, lamelle 3 
eee BHD EG; COLGUL OG isis fet savas eer eee ee stot iee decades evoebeiaterviiesss 
Arista longer, hyaline, rough; stem short piliferum 
4 {st not tomentose; Is. spreading, recurved ...............juniperinum 
St w. dense tomentum ; Is, rant to straight woes strictum 
5 { Ls. Ww. wae pellucid wings; caps. sess of Atiglod icicisscciiceed gracile 
5 ike. longer, w. V. narrow margins; caps. a angled jiu iad Coren 6 
g | Caps. oblong; no distinct perich. Is.; lam . form 
( Caps. cubic; perich. ls. long, membranous; ron pe pacar 
POTTIA, 
1 | oo “ol or rudimentary 2 
Peristom il 
2 Nery some caps. oval on short seta pusilla 
Nerve vines lamelle 3 
