BARNES — NORTH AMERICAN MOSSES. 233 



THUIDIUM, p. 321. 



I. Plants small (to 5 cm.), delicate, creeping, IS pinnate. 



Costa of stem leaves wide [\ leaf base). 



Branches papillate, leaf cells 6// diam. . . T. pygmaenm, 322. 



Branches papillate, leaf cells 9/<, longer at margin T. minutulum, 322. 

 Costa of stem leaves narrow {^ leaf base). 

 Leaf cells with several minute papillae . . . T. scitam/ 323. 

 Leaf cells with one papilla (rarely two). 



Branch leaves roundish ovate, short acuminate T, Virginianuiii,' 324. 

 Branch leaves ovate lanceolate, long acuminate T. microphyllum,' 324. 



n. Plants larger (to 10 cm.), creeping, 1-3 j^innate, forming exten- 

 sive flat mats. (Ill) 



Perichaetial leaves ciliate, costa of stem leaves not reach- 

 ing point T. delicatulnm, 325. 



Perichaetial leaves not ciliate. 



Costa of stem leaves filling point . . . T. reco^nitnni, 325. 



Costa of stem leaves % length . . . . T. Philiberti, 44^a. 



[T, paludosuni may be sought bore.] 



III. Plants large (to 10 cm.), erect or ascending, l-jnnnate, in 



wide tufts. 

 Leaf cells roundish or oblong (1 : 1-2), strongly papillose 



both sides T. abietinum, 326. 



Leaf cells long rhombic to linear (1 : 3-6), smooth above. 



Stem leaves soft, sub-clasping, decurrent . . T. Blandovii, 326. 

 Stem leaves rigid, plicate-striate, sub-decurrent T. paludosuni,* 330. 



This genus has been revised by G. N. Best, Bull. Torr. Bot. Club 23: 

 78-90. 1896, and we have been able to avail ourselves of his suggestions 

 by recalling MS. T. tamariscinum Hedw. and T. remotifolium Grev. 

 are not N. American; T. ereetum Duby = T. delicatulum L.; H. calyp- 

 tratum Sull. = T. microphyllum (Sw.) Best, an earlier name ioxH.gra- 

 cile B. & S., and to it T. lignicola Kindb. is referred as a variety; T. Al- 

 leni Aust. is probably a sterile form of T. delicatulum L. 



1 See Appendix, no. 441, Not recognized by Best. 



^T. Virginianum (Brid.) Lindb. = Hypnum gracile Lancastriense S. & L., L. J. 

 Man. 324. 



3 T. microphyUum (Sw.) Best — Hypnum gracile B. & S., L. i& J. Man. 324. See also 

 Appendix, no. 442. 



* T. paludosum (Sull.) Ran & Hervey = Hypnum paludosum Sull., L. & J. Man. a30. 

 See also Appendix, no. 443. 



