POLYTRICHUM. 39 



/Leaf-margin entire, inflexed over the lamellaa (capsule angled) 2 



\Leaf-margin more or less toothed, not inflexed 5 



f Ls. bluntish, more or less cucullate at apex, nerve scarcely excurrent 



2-j 5. sexangulare 



[Ls. aristate at apex 3 



/Arista long, hyaline, very rough 6. piliferum 



^\ Arista short, coloured 4 



{Stem not tomentose ; ls. spreading ; capsule oblong 7. juniperinum 

 Stem densely tomentose ; Is, erect; capsule small, cubic 7*. strictum 



(Capsule 4-6 angled ; ls. with narrow tapering points, border-cells of lamellae 

 smooth 6 

 Capsule not angled ; ls. either with short wide points or with border-cells of lamel- 

 lae papillose 8 



I Capsule cubic, sharply angled ; border-cells of lamellae grooved longitudinally 

 6-j io. commune 



[Capsule oblong; border-cells of lamellae similar to the rest, not grooved 7 



/Capsule distinctly angled ; basal cells of ls. very long and narrow ...9. formosum 



' \ Capsule obscurely angled ; basal cells shorter and wider 8. gracile 



["Ls. with short, wide points, border-cells of lamellae similar to the rest, thin, smooth 



9 



1 Ls. with long, narrow points ; border-cells of lamellae large, thickened, papillose 

 I 10 



f Capsule very short, columella cylindric ; ls. obtusely toothed 1. nanum 



\Capsule cylindric, columella winged ; ls. sharply toothed 3. aloides 



/Capsule cylindric, erect or nearly so ; border-cells of lamellae round 3. umigerum 

 \ Capsule tumid, inclined ; border-cells oval ^. alpinum 



A. POGONATUM. 



Capsule oval or cylindrical, in section circular, not or hardly 

 apophysate. 



1. Polytrichum nanum Neck. {Pogonatum nanum P. Beauv., 

 Schp. Syn.) (Tab. X. A.). 



Plants gregarious, deep green ; stems very short, \ to £-inch 

 high, simple, naked below, intermixed with green protonema at 

 base. Leaves from an erect sheathing base, spreading, with a 

 lingulate or ovate-lanceolate limb, obtusely pointed, with the 

 margin erect at apex, bluntly toothed from about the middle of 

 the limb, the teeth brownish, composed usually of a single cell, 

 remote below, more crowded above ; nerve percurrent, bluntly 

 toothed at back of apex, very broad on the face of the leaf, and 

 covered with 30-40 lamellae, occupying the greater part of the 

 limb to near its base, in section of 6-8 small equal rounded cells. 

 Areolation rounded-hexagonal above, hexagonal at base of limb 

 and basal margin, narrow-rectangular at mid-base. Seta thin, 

 flexuose, variable in length. Capsule small, erect or inclined, 

 oval or almost spherical, with a rostellate lid, wide-mouthed and 

 turbinate after the fall of the lid, smooth. Calyptra hardly reach- 

 ing the base of the capsule. Peristome teeth 32, rather large in 

 proportion to the size of the fruit. Columella cylindrical. 



