ANDRE^A. 25 



strongly papillose at back, especially in the upper part. Areola- 

 tion narrowly rectangular at base, sinuose, with very incrassate 

 walls, gradually shorter upwards, in the upper-»half of the leaf 

 rounded-hexagonal, almost always more or less angular, arranged 

 in longitudinal rows. Autoicous ; male flower on the apex of a 

 separate branch ; perichastium large, inner bracts convolute, 

 broadly oblong, obtusely pointed ; outer bracts strongly papillose, 

 the inner almost smooth, but usually slightly papillose towards 

 the apex. 



Var. ji. acuminata Schp. More robust. Leaves spreading, 

 acuminate, with longer papillae. 



Var. y. gracilis Schp. Stems very slender, branched, reddish ; 

 leaves more distant, broadly oblong-lanceolate, suberect ; perichae- 

 tium narrow, cylindric. 



Var. 8. alpestris Thed. {A. alpestris Schp. Syn.) Densely 

 cushioned ; black-brown, shiny. Stems very slender, much 

 branched. Leaves small, crowded, closely imbricated when dry, 

 obtuse, cells less incrassate , less distinctly papillose. 



Var. e. sparsifolia Lindb. {A. sparsifolia Zett., Schp. Syn.) 

 In small lax tufts, stems very slender and fragile, flexuose, with 

 few branches. Leaves small, distant, spreading, the uppermost 

 secund, lanceolate, gradually acuminate, acute, more shortly 

 papillose. 



Hab. Mountain rocks ; common. The vars. 0, S, t, on the higher mountains ; 

 var. alpestris rare. Var. sparsifolia, Ben More, Perthshire. 



A very variable species within certain limits, principally in the form and direction 

 of the leaves ; these are often more or less secund ; when markedly so it is the var. 

 homomalla Thed. The vars. flaccida and sylvicola Schp. agree with var. acuminata 

 in having the leaves gradually tapering to the summit, but do not appear to be very 

 marked forms. The var. alpestris has been frequently considered a species, but the 

 differences are too slight to render this admissible ; the leaves vary in size, their close 

 imbrication when dry and the less papillose areolation constitute almost the only 

 points of distinction. The var. sparsifolia is a. more striking form, but its structural 

 differences are very insignificant. 



A. obovata Thed. , a nearly allied species hitherto only found in Norway, differs 

 in the leaves, broader below, more acuminate, not papillose ; in fact much resembling 

 those of A. alpina, but smaller, and more longly acuminate, with the basal margin 

 quite entire, and with larger cells. 



2. Andresea alpina Smith {Lichenastrum alpinum Dill.) 

 (Tab. VIII. E.). 



A larger plant than the last species, less slender and fragile, 

 1-3 inches high, in larger, looser tufts, fastigiate branched, of a 

 rich purplish red. Leaves larger, broader, obovate, spathulate, 

 acuminate or obtusely pointed, panduriform by contraction 



