48 MUSCI-ACROCARPI-PER1STOMI. [Polytrichum. 



chostomum. Leaves elliptic-lanceolate, acuminated, margined, entire, 

 waved, crisped when dry; nerve strong. Perichcetial leaves nearly as 

 long as the fruit, much acuminated. Capsules nearly sessile, often on 

 very short branches, but terminal, oblong, smooth. Lid conico-acu- 

 minate. Calyptra sometimes split on one side. Peristome red, teeth or 

 cilia very slender, rigid. 



22. Polytrichum. Linn. Hair-Moss. 



Seta terminal. Peristome single, of 32 or 64 short equidis- 

 tant incurved teeth; their summits united to a horizontal mem- 

 brane, closing the mouth of the capsule. Calyptra dimidiate, 

 small. (Muse. Brit. t. I.) — Named from noxvg, many, and doi%, a 

 hair, in allusion to the calyptra being generally invested with a 

 dense mass of hairs, which are indeed the "fila succulenta " of the 

 flower, carried up by the calyptra. — A very natural Genus. 

 Leaves mostly rigid, resembling those of an Aloe in miniature : 

 the nerves more or less distinctly lamellated or striated. 



* Calyptra naked. (Catharinea, Ehrh.) 



1. P. unduldtum, Hedw. (undulated Hair-Moss); leaves mem- 

 branous lanceolate waved the margins plane toothed denticulate 

 the nerve winged, capsule cylindrical curved, lid subulate. 

 Hedw. St. Cr. v. 1. p. 16, 17. Turn. Muse. Hib. p. 91. Fl. Brit, 

 p. 1382. E.Bot. t. 1220. Schwaeyr. Suppl. v. I. p. 330. Hobs. 

 Brit. Mosses, v. 1 . n. 1 3. Drum. Muse. Scot. v. 2. n. 20. Muse. 

 Brit. ed. 2. p. 43. t. 10. — Bryum undulatum, Linn. — Bill. Muse, 

 t. 46./. 18. 



Moist shady banks and in woods, frequent. Fr. Oct. 



2. P. hercynicum, Hedw. (Hercynian Hair-Moss); leaves 

 lanceolate rigid entire their sides involute, their nerve broad 

 impressed with furrows, capsule oblong suberect, lid conical. 

 Hedw. St. Cr. v. 1. p. 15. Fl. Brit. p. 1381. E. But. t. 1209. 

 Schwaegr. Suppl. v. 1. p. 329. 31usc. Brit. ed. 2. p. 44. t. 10. 



On elevated mountains, abundant. Fr. July. — The leaves are, as it 

 were, intermediate in texture between the preceding and following 

 species. 



** Calyptra covered with succident filaments. 



-j- Leaves entire, their margins involute. 



3. P. piliferum, Schreb. (bristle-pointed Hair-Moss); leaves 

 lanceolato-subulate their margins involute entire terminating in 

 a pellucid hair-like point, capsule ovate obtusely quadrangular 

 furnished with an apophysis, lid conical. Schreb. Fl. Lips. p. 74. 

 Turn. Muse. Hib. p. 82. Fl. Brit. p. 1375. E. Bot. t. 1199. 

 Schwaegr. Suppl. v. 1. p. 313. Hobs. Br. Mosses, v. 1. n. 14. 

 Drum. Muse. Scot. v. 2. n. 17. Muse. Brit. ed. 2. p. 44. t. 10. — 

 P. commune, y. Linn. — Dill. Muse. t. 54. f. 3. 



Heathy places, frequent. Fr. Sprang. — Stems short, bare of leaves 

 at the base 



