248 ORTHOTRICHACE^E. 



A. RUPESTRIA. 



1. Orthotrichum rupestre Schleich. (Tab. XXXIV. K.). 



In rather large loose tufts, dark olive brown, rarely more 

 yellow or green, soft, but rigid when dry, taller than O. cupulatum 

 and O. anomalum, 1-2 inches high, the stems sometimes a little 

 spreading and decumbent. Leaves broadly lanceolate, tapering, 

 or suddenly acuminate, but not acute, spreading and a little 

 recurved, or less commonly straight and erecto-patent, when dry 

 straight and imbricated, often very closely and regularly ; cells 

 small, rounded-hexagonal or more incrassate and rounded, in one 

 or two layers, opaque, more or less strongly papillose ; papillae 

 simple or bifid. Capsule immersed or emergent, oval or oval- 

 oblong, brownish yellow, with 8 rather faint short ribs, very 

 rarely with 8 obscure intermediate ones ; at base tapering 

 gradually into the very short seta; when dry and empty the 

 capsule becomes narrower, darker, reddish brown, more strongly 

 striate or sulcate (sometimes however nearly smooth), about the 

 same width throughout or sometimes slightly contracted below 

 the mouth. Stomata superficial, mostly occurring at about the 

 middle of the capsule. Calyptra yellowish, with numerous long 

 hairs. Peristome teeth in 8 pairs, finally splitting into 16 bifid 

 teeth, yellowish 'white, erect or spreading when dry, usually 

 faintly papillose ; processes 8, variously developed, or wanting. 

 Autoicous. 



Var. /?. Sturmii Juratz. {Orth. Sturmii Hornsch., plur. 

 auct). Capsule more suddenly contracted into the seta. In 

 addition to this, the most important character, the following 

 points are more characteristic of the variety than of the type; — 

 leaves straighter, more erect, upper leaf cells more frequently in 

 two layers, or even three or four, colour darker green or blackish ; 

 texture more rigid; peristome teeth almost smooth, processes 

 wanting. 



Var. y. Franzonianum Vent. (Orth. Franzonianum DeNot.; 

 Orth. Skawii De Not., Epil., non Wils.J. In small green tufts 

 on trees; areolation rather laxer and less incrassate; capsule 

 small, the striae rather more distinctly marked. 



Hab. Rocks and walls in mountainous districts, not uncommon ; the var. j8 

 rare ; the var. 7 on trees, Fortingal, Perthshire (Dixon, i8gj). Fr. late summer and 

 autumn. 



0. rupestre is a very difficult species to describe. It presents few characters of 

 distinction at once marked and stable ; indeed it really represents a group of forms 



