70 MUSCI-PLEUROCARPI-PERISTOMI. [Leucodon. 



Schwaegr. Suppl. v. 1. p. 105. Hobs. Br. Mosses, v. 1. n. 26. 

 Muse. Brit. ed. 2. p. 74. t. 14. — Pterigynandrum gracile, Hedw. 

 St. Cr. v. 4. t. 6. — Grimmia ornithopodioides, Mohr. — Hypnum 

 graeile, Linn. — Dill. Muse. p. 41./. 55. 



Rocks, in subalpine and hilly countries, frequent. Fr. Winter. — A 

 careful examination of good specimens of the fruit of this plant will 

 bring to view something like an inner peristome, a narrow membrane, 

 similar to that which unites the base of the cilia of Neckera, yet termi- 

 nating so irregularly as not to justify us in placing this among the mosses 

 which have a double peristome. 



3. P. filiforme, Schwaegr. (filiform Pterogonium); stems 

 irregularly branched curved, leaves ovate subacuminated con- 

 cave their margins recurved serrated, nerve single or forked 

 short faint, lid conical. Schwaegr. Suppl. v. 1. p. 100. E. Bot. 

 t. 2297. Muse. Brit. ed. 2. p. 75. t. 14 — pterigynandrum fili- 

 forme, Hedw. St. Cr. v. 4. t. 7. — Pterogonium cwspitosum, E. Bot. 

 t. 2526. — Hypnum cylindricum, Dicks. Cr. Fasc. 2. p. 12. Fl. 

 Brit. p. 1280. 



Rocks, upon the mountains of Scotland and Ireland. Fr. Summer. 

 — In this and the preceding species, the leaves are closely imbricated 

 and subsecund, but the present plant is much the smaller of the two and 

 more irregularly branched. The cellules of the leaves are larger than in 

 P. graeile, and project on the back and at the margins, which give the 

 foliage a papillose appearance, as in Hypnum catenulatum, H. proliferum, 

 and a few others. 



33. Leucodon. Schwaegr. Leucodon. 



Seta lateral. Peristome single, of 32 teeth, closely united in 

 pairs. Calyptra dimidiate. (Muse. Brit. t. 2.)— Named from 

 Xevstog, white, and oduv, a tooth, on account of the pale-coloured 

 teeth of the British species, the one on which the Genus was 

 founded. 



1. L. sciuroides, Schwaegr. (Squirrel-tail Leucodon); leaves 

 closely imbricated ovato-cordate acuminated striated, capsule 

 oblong. Schwaegr. Suppl. v. 2. p. 1. Hobs. Br. Mosses, v. 1. 

 n. 51. Muse. Brit. ed. 2. p. 112. t. 20.— L. Morensis, Schwaegr. 

 Suppl. v. 1. P. II. p. 2, and v. 2. P. I. t. 125.— Dicranum 

 sciuroides, Sw.—Fl. Brit. p. 1215. E. Bot. t. 1903 — Trichosto- 

 mum sciuroides, Mohr. — Pterogonium sciuroides, Turn. Muse. Hib. 



p. 32 Hypnum sciuroides, Linn — Dill. Muse. t. 41. /. 54. 



Frequent on trunks of trees, in England ; rare in Scotland. Fr. (very 

 scarce) Summer.— Stems long, creeping on the bark of trees. Branches 

 ascending, often tumid, when it becomes the L. Morensis of Schwaegr. 

 Leaves concave, those of the perichcetium long, cylindrical, sheathing, 

 especially the inner ones, which are half as long as the fruitstalk, and 

 which closely envelope it :* this latter is about an inch long. Lid ros- 

 trate. The perfect fruit has rarely been gathered but by C. Lyell, Esq. 

 in the New Forest, Hants, and by Mr. Borrer in Sussex. 



