ANDRE^A. 27 



Type. Leaves erecto-patent or secund, gradually narrowed 

 from base upwards, entire, lamina usually of 3-5 cells width in 

 upper part of limb. 



Var. /3. grimsulana Hook. & Wils. {A. Rothii var. frigida 

 Lindb., Braithw. Br. M. FL). More robust, taller, usually of a 

 more reddish tinge. Leaves broader, gradually narrowed from 

 the base, more solid. 



Var. y. hamata Lindb. Intermediate between the type and 

 var. falcata. Leaves falcato-secund, gradually narrowed from 

 base upwards, lamina narrow, but continuous above, entire. 



Var. S. falcata Lindb. {A. falcata Schp. Syn.). Leaves falcato- 

 secund, abruptly narrowed above the broader, obovate base to a 

 long, linear limb, the lamina continued to apex, very narrow and 

 indistinct in the upper part, usually of about 2-3 series of cells ; 

 frequently distinctly notched towards the apex. 



Hab. Mountain rocks, frequent. The var. $, wet rocks on high mountains. 

 The var. 5 as frequent as the type. 



The characters which mark the vars. hamata and falcata are very ill-defined ; 

 the sudden narrowing of the leaf above the base is by no means constant even in all 

 the leaves from a single stem ; the relative width of the lamina in the upper part 

 varies very much also (it must be remembered that the young comal leaves do not 

 afford any safe guidance in this respect) ; and a faint notching may occasionally be 

 seen in the upper leaves even of the type. The form of leaf typical of the var. falcata 

 is also associated occasionally with a spreading (not falcato-secund) position of the 

 leaves. 



In the forms with a narrow base to the leaves the lower cells are more distinctly 

 rectangular ; in the falcata forms they are usually more rounded and very little 

 different from the upper cells except those very near the nerve. In examining the 

 upper cells of this species it should be noted that on the surface of the leaf they are 

 angular and more or less regularly hexagonal, but in the interior of the cell the wall is 

 thickened in such a way that the cell cavity is rounded, or punctiform, hence the 

 areolation takes a different aspect according as the microscope is focussed on the sur- 

 face of the leaf or slightly lower down. 



The lower part of the stem and innovations is not unfrequently clothed with 

 minute scale-like leaves, ovate, with a short apiculus. 



* Andresea crassinervia Bruch. (Tab. VIII. G.). 



Differs from A. Rothii only in the stronger nerve, the limb of 

 the leaf very narrowly contracted from just above the expanded 

 base, the lamina in the upper part extremely narrow, sometimes 

 ceasing below the apex so that the nerve is slightly excurrent. 



Var. /8. Huntii Braithw. (A. H 'until Limpr.). Taller ; 

 leaves longer with a narrower nerve. Perichaetial bracts shorter, 

 obtuse or apiculate, papillose. 



Hab. Alpine rocks ; apparently very rare. The var. &, Lake District. 



