26 ANDRE^ACEiE. 



just below the middle, erecto-patent when moist, when dry more 

 closely imbricated, smooth, glossy, nerveless. Margin distinctly 

 denticulate above the base, entire in the upper part of the leaf. 

 Cells smooth, oval or rounded-hexagonal at apex, in parallel rows, 

 gradually becoming more elongate and sinuosely angular down- 

 wards, at base extremely narrow and sinuose, with very incrassate 

 walls. Autoicous. Perichaetial bracts resembling the comal leaves, 

 but larger, broader, convolute, more shortly acuminate. 



Var. /3. compacta Hook. Densely cushioned, dark purplish 

 black. Branches straight, equal ; leaves closely imbricated. 



Var. y. fiavicans Hook. Stems elongated, filiform, the leaves 

 more distant, laxly imbricated, yellowish. 



Hab. Mountain rocks, frequent. The var. $ on the higher mountains of Scot- 

 land and Wales ; the var. y on Ben Nevis. 



This fine and distinct species, though distributed all over Britain and not rare on 

 our mountains, is almost unknown on the Continent, being only recorded from a few 

 localities in Norway. It is in its usual growth a much taller and less rigid plant than 

 any of the forms of A. fetrofhila, and is indeed more likely to be mistaken for a 

 species of Hepatic, such as Nardia emarginala, with which it may occasionally be 

 found associated, and to which, indeed, it bears considerable superficial resemblance, 

 than for any other species of moss. The var. Jlavicans has some resemblance to A. 

 Hartmani, another of the Scandinavian species, which, however, may be known by 

 its more obtuse, entire leaves, and larger areolation. 



3. Andresea Rothii Web. & Mohr. {A. rupestris Schp. Syn.) 



(Tab. VIII. F.). 



In small, dense, blackish tufts, laxly coherent when moist. 

 Stems erect or decumbent, slender, very fragile when dry, less 

 than one inch high. Leaves crowded, erecto-patent or more 

 usually turned to one side, and generally more or less falcate ; 

 from an oblong, oval, or slightly obovate base, either gradually 

 or suddenly narrowed to a long lanceolate or narrowly linear 

 limb, tapering to an obtuse point. Nerve strong, \-\ width of 

 leaf at base, reaching to apex or excurrent (in sub-species cras- 

 sinervia), occupying the greater part of the limb in the upper part. 

 Margin plane, entire or faintly dentate at apex. Cells rounded, 

 hexagonal and punctiform above with very incrassate walls, 

 smooth, not much altered below except at mid-base, where a few 

 rows of cells on each side of the nerve are narrowly rectangular. 

 Autoicous. Inner perichaetial leaves convolute, sheathing, nerve- 

 less or thinly nerved, broadly ovate, gradually or somewhat 

 abruptly acuminate, narrower and more tapering than in the two 

 previous species. 



