192 DIPLOPERISTOMI. [_Timmia 



HAB. Exceedingly rare on rocks on the banks of the Isla, 

 above Airly Castle, Forfarshire. Discovered by Mr. 

 Drummond in 1824 ; but always barren. 

 Plant growing- in dense tufts three to four inches high, erect, 

 slightly branched, brown below, from the decayed foliage and 

 roots, green above. Leaves linear-lanceolate, erecto-patent, 

 plane or slightly recurved at the margin, serrated, a little 

 carinated, with a strong nerve reaching to the point, crisped 

 when dry. Fruitstalk one to two inches long, reddish. Cap- 

 sule oblongo-obovate, inclined in a, cernuous or horizontal in (3. 

 Lid hemispherical, slightly mammillate. 



It is to be hoped that the fructification of this valuable addi- 

 tion to the British Muscologia, will one day be detected by its 

 acute discoverer. The stems and foliage of the Scottish speci- 

 mens are remarkably fine, as much so as those growing upon 

 the alps of Savoy bordering upon Italy, where the plant is far 

 from uncommon, and where it bears fruit abundantly. The 

 only difference between the two Hedwigian species that we can 

 find is the direction of the capsule ; the leaves being the same 

 in both. The American state of it is remarkable in having the 

 capsule pass through the fissure of the calyptra, which then 

 remains attached to the upper part of the fruitstalk, surround- 

 ing it with ^its convolute base, and resembling, as my friend 

 Mr. Parker has justly observed, the spatha in the genus Nar- 

 cissus. This is found from Pennsylvania to the country be- 

 tween Point Lake and the Arctic Sea. 



XXXV. BRYUM. 



GEN. CHAR. Fruitstalks terminal; Peristome double; the 

 exterior of 16 teeth; the interior of a membrane cut into 

 16 equal segments, with filiform processes frequently 

 placed between them; Calyptra dimidiate. (TAB. III.) 



For the same reasons as we have united Leskea with Hypnum. 

 have we incorporated Pohlia of Hedwig with Bryum. Meesia, 



