HYPNUM. 467 



* Hypnum falcatum Brid. (Amblystegium falcatum Lindb.) 

 (Tab. LVIII. A.). 



More robust, of a deeper, often orange-brown colour, stems 

 stouter, more distantly and irregularly pinnate or sub-pinnate, 

 the branches often few and more or less ascending or erect, not 

 regularly plumose ; radicles few or none ; leaves crowded, much 

 larger and longer than in H . commutatum, rendering the stems 

 and branches much stouter ; more regularly and strongly falcato- 

 secund, more rigid and hardly flexuose when dry, 1-2 lines long, 

 widely or narrowly oblong-lanceolate from a less expanded, not 

 cordate-triangular base, more gradually but more widely acumi- 

 nate, of more solid texture ; nerve very strong and thick, often 

 purplish ; cells more incrassate, linear-flexuose, the angular 

 strongly incrassate, orange-brown, often opaque, forming less 

 distinctly marked decurrent auricles. Seta and capsule rather 

 shorter and stouter. 



Var. (3. gracilescens Schp. Very slender and graceful, in 

 soft, rather dense tufts, procumbent or ascending, stems irregularly 

 divided, the divisions long, slender, almost simple or with few, 

 somewhat pinnate, very short branches. Leaves very regularly 

 and neatly falcato-secund or circinate, very small, about \ line 

 long, glossy, hardly plicate, nerve moderately strong, reaching | 

 the length of the leaf. Cells narrow, but rather short. 



Var. y. virescens Schp. (H. imgatum Zett.). Aquatic; 

 dark green or blackish ; stems longly denuded, clothed with the 

 bristle-like nerves of the old leaves. Leaves slightly falcato- 

 secund or straight and erecto-patent and lightly secund only at 

 the tips of the branches, hardly plicate ; ovate-lanceolate or 

 narrowly triangular-lanceolate, tapering to a wide and often 

 rather obtuse point, or acute ; nerve extremely thick and wide, 

 reaching apex or lost just below; angular cells hardly distinct. 

 Paraphylliay^w or none. 



Hab. Bogs, principally at higher elevations than H. commutatum ; frequent. 

 The var. £ on wet mountain rocks, rare. Yorkshire ; Staffordshire ; Ben Lawers. 

 The var. 7 in calcareous springs and mountain streams, very rare. Fr. summer. 



In habit H. falcatum is so different from typical H. commutatum that the two 

 could hardly fail to stand as separate species were it not for the fact that numerous 

 intermediate forms occur, principally on the side of the latter, forming a more or 

 less graduated passage from the one to the other. Thus robust forms of H. 

 commutatum with densely radiculose stems and regular pinnate, branching will give 

 rise to stout, almost simple offshoots with the long, narrow leaves and the general 

 characters of H. falcatum. The latter also frequently occurs in a somewhat slender 

 form, showing much resemblance to H. ■vemicosum and some forms of H. exannu- 

 latum, but readily distinguished from the one by the auricles and from the other by 



