Jennings: Manual of Mosses — 22. Polytrichaceae 169 



leaf lincar-rectanguIar, mainly parenchymatous, moderately incrassate, in ;niddle 

 portion of sheath relatively wider, about .010 x .040-. 090 mm, both prosen- 

 chymatous, in inflexed margin of limb obliquely quadrate-rectangular-elongate, 

 decidedly incrassate; lamellae about 30-40, usually 6-7 cells high, the terminal 

 cell somewhat broader and with an abruptly narrowed shortly prolonged apex; 

 perichaetial leaves more hyaline with a longer sheathing base and a considerably 

 longer slightly dentate arista: seta erect, flexuous, lustrous, about 4-6 cm high, 

 somewhat sinistrorse; capsule tetragonal-oblong, about 3-5 x 2-2.5 mm, sharply 

 angled, reddish to dark chestnut-brown when old, apophysis short but rather 

 distinct, capsule p>endulous to horizontal; spores round, smoothish, about .008- 

 .011 mm, mature in midsummer; cells of exothecium elongate-hexagonal to 

 quadrate-hexagonal, the perforation linear-oblong, about half as long as cell. 



Heathlands, dry pastures, thin woods, etc., in hilly or mountainous regions 

 the world over. It occurs from Arctic America south to North Carolina. 



Now known from eighteen counties in western Pennsylvania. Specimen figured: On 

 ground in dry pasture, near Kittanning, Armstrong Co., Sept. 24, 1904. O.E.J. 



5. PoLYTRlCHUM ALPESTRE Hoppe, Schwaegtichen* 



(Polytrichum strictum Banks, Menzies) 



Plate XXXIII 



Large mosses forming dense tufts up to 20 cm deep, tufts deeply matted 

 with a dirty-white tomentum: stems branching, rather slender, often matted 

 tomentose to within 2-3 cm of the apex; leaves more or less rigidly appressed- 

 imbricate when dry, when moist with the lance-linear limb spreading and 4-5 

 mm long, from an oblong sheathing base about 1.5 mm long, margin of limb 

 entire, inflexed, the apex rather abruptly narrowed into a linear, reddish- 

 pellucid, slightly serrate acumen, leaves dorsally serrulate nearly to the sheath- 

 ing base, the costa bearing ventrally about 25-35 lamellae; lamellae 5-8 cells 

 high, the terminal cell broader and abruptly narrowing to an obtuse short 

 acumen, as seen in cross-section; areolation of sheathing base almost hyaline, 

 not so markedly incrassate, the median basal rectangular, 4-8 times as long as 

 broad, towards the margin and upwards in the sheathing portion narrower, 

 longer, either prosenchymatous or parenchymatous, cells of inflexed margin of 

 limb obliquely quadrate or rectangular to linear-oblong in the border, incras- 

 sate; perigonial leaves of male plant obovate-orbicular, the costa broad, lamel- 

 late on the uppver half, percurrent in a broadly acute acumen: seta erect, slen- 

 der, wiry, sinistrorsly flexuous, 4-8 cm long, lustrous, rich chestnut-brown 

 below and lighter above; capsule more or less cubic, 2-3 mm long, acutely 

 angled, papillose, yellowish to chestnut-brown, apophysis distinct; cells of 

 exothecium more or less hexagonal, the central pore round to oblong, often 

 one-third the diameter of the whole cell; peristome about 0.2 mm high, teeth 

 rather slender; calyptra yellowish-brown, covering the capsule; operculum flat- 

 tened, the rostrum about 0.5 mm long. Evidently mature in midsummer. 



* Frye, T. C, m Grout's Moss Flora, reduces this to a variety of P. jumperirium, i.e. 

 P. juniperinum var. alpestre Bryologia Europaea. 



