ORTHOTRICHUM. 253 



form collected by Spruce near York, with rigid, closely appressed leaves ; this may be 

 the sub-spec, strktum Vent. Curiously enough, the American plants of O. Lyettii are 

 almost always without the brown gemmae so characteristic of our British plant ; one of 

 their forms, too, is markedly distinct in the wide yellowish patches with flexuose 

 branches and leaves crisped when dry ; this may, however, possibly be a different 

 species. 



The brown gemmae (Conferva Orthotric hi of old authors) are not confined to 0. 

 Lyellii, being found on other species such as 0. affine and O. speciosum, but they are 

 much more abundant on our present plant, only occurring on the others sporadically. 



7- Orthotrichum speciosum Nees. (Tab. XXXV. E.). 



Taller than O. affine, yellowish green or tinged with red ;. 

 leaves spreading, imbricated when dry, oblong-lanceolate, tapering, 

 acute, margin recurved to apex ; basal cells narrowly rectangular, 

 upper distinct, very incrassate, rounded or irregularly elliptical, 

 papillose. Capsule emergent or fully exserted, on a long seta ; 

 oblong-cylindrical or oval-oblong, hardly narrowed below the 

 mouth, tapering into a long neck, which is less conspicuous when 

 dry ; striae 8, very faint and almost obsolete before the spores are 

 shed, more distinct afterwards, while old capsules are often 

 distinctly sulcate. Peristome double, outer of 16 bifid teeth in 8 

 pairs, opaque, papillose, reflexed when dry so that a considerable 

 part of the upper half the tooth is appressed to the wall of the 

 capsule ; processes 8, white, large, papillose, incurved. Autoicous. 



Hab. Trees in mountainous districts, rarely on rocks ; not common. Fr. late 

 summer. 



Readily known from 0. affine, and indeed from most of the allied species, by the 

 long seta and exserted capsule which is almost smooth until old and empty. O. 

 leiocarpum differs in the immersed capsules, O. Shawii in the differently revolute 

 peristome, the absence of inner processes and the more immersed fruit. Though 

 common on the continent it is one of our rare species. 



8. Orthotrichum affine Schrad. (Tab. XXXV. F.). 



In small loose tufts, dull green ; leaves spreading, when dry 

 straight and more or less imbricated, broadly oblong-lanceolate, 

 sub-acute, margin widely revolute ; areolation rounded-oval or 

 hexagonal-rounded, incrassate, papillose. Capsule emergent or 

 very slightly exserted, oblong-cylindrical with a rather long 

 tapering neck, ribs 8, each of 3-4 rows of cells ; greenish, when 

 old brown, sulcate, and very slightly contracted below the mouth. 

 Stomata superficial, rather below the middle of the capsule ; 

 calyptra narrow, greenish, darker above, slightly hairy ; vaginula 

 smooth ; peristome double, outer of 16 teeth in 8 pairs, reflexed 

 when dry so as to touch the capsule almost with their whole 

 length, papillose, processes 8, filiform. Autoicous. Spores 20-25 V-- 



