284 TIMMIACEjE. 



Hab. Stony ground on mountains ; very rare and sterile on two or three of the 

 Scotch mountains. Fr. summer. 



The most obvious character by which this species is distinguishable in the field 

 from the next, is the wide sheathing leaf base ; under the microscope the nerve, not 

 papillose at back or front above, readily separates the two ; the dentation of the 

 nerve towards apex is usually faint and may be quite absent. 



2. Timmia norvegica Zett. (Tab. XXXIX. H.). 



Resembling the last species, but differing in the leaves, which 

 are much elongated towards the summit of the stem, 3-4 lines or 

 even more, bright green, forming a cuspidate tuft, arcuate and 

 twisted when dry and frequently falcato-secund, sub-tubular, 

 deciduous, linear-lanceolate, hardly enlarged at the base or 

 sheathing; nerve covered for the greater part of its length both 

 at back and front , with dense, ascending papillse ; not toothed at 

 back. Cells above as in the last species, smooth or papillose, the 

 basal elongated, chlorophyllose, only a few of the lowest orange, 

 two or three rows at the line of insertion very thin, fragile, 

 hyaline. Capsule resembling that of the last ; cilia of inner 

 peristome without appendages. Dioicous. 



Hab. Mountain rocks and earth, very rare ; Ben Lawers and Den of Airlie, 

 Scotland ; Powerscourt Waterfall, Ireland. Fruit not found in Britain. 



Until recently the fruit of this species had not been recorded, and it has now 

 only been found sparingly in the Tyrolese Alps. The characters italicised above will 

 readily distinguish it from the last. The elongated leaves appear on the old stems 

 alternately with the shorter ones, in interrupted tufts, and are usually falcato-secund. 

 The leaves are very readily deciduous, owing to the delicate structure of the lowest 

 rows of the basal cells. I have found this species on Ben Lawers and the adjacent 

 mountains in many localities (sometimes forming large bright green tufts 5 or 6 inches 

 high), but without detecting a single stem of T. austriaca. Boulay suspects this to 

 be a form of that species induced by great moisture, but that view seems, to say the 

 least, improbable. 



It is curious that the papillosity of the cells of the lamina in both these species 

 should be so uncertain in character. As a rule the leaves are quite smooth, but one 

 may be seen here and there with all the cells, except quite the basal ones, distinctly 

 and even strongly papillose. 



Order XVII. BARTRAMIACE^E. 



Caespitose, usually tall and robust mosses, the stems often 

 producing whorled innovations below the flowers. Leaves usually 

 narrow in outline and acute, areolation narrow, usually sub- 

 rectangular, almost always papillose. Calyptra small, fugacious, 

 cucullate. Capsule globular or nearly so, almost always without 

 a neck, mostly cernuous and almost always striate. Peristome 



