256 ORTHOTRICHACE^E. 



orange. Stomata about the middle of the capsule, immersed, 

 mostly about half closed with the overlapping cells ; peristome 

 double, outer of 8 pairs of reflexed teeth ; processes 8. Calyptra 

 short, inflated, smooth and shining ; naked or with very few- 

 hairs, /taife. Spores small, 12-15 /i. Autoicous. 



Hab. Trees, rare. Fr. spring. 



This is peihaps the smallest of our species, and easily known by the dwarf 

 compact habit, the rather obtuse leaves, and the pale yellow, smooth inflated calyptra. 

 The distinction between this species and 0. pumilum Swartz (turn Dicks.) is very 

 slight and I cannot help thinking unimportant ; Venturi bases it mainly on the form of 

 the base of the capsule, or rather its neck, but his figures show hardly any difference 

 between the two plants, and according to Philibert this character is quite valueless ; 

 the latter author makes the degree of closing of the stomata and the time of fruiting 

 the specific distinction, O. Schimperi having the stomata more open and the fruit 

 ripened a month earlier, but the difference, even as described by him, is very small. 

 Specimens which I gathered in Northamptonshire in 1885, while showing the stomata. 

 of 0. Schimperi have the capsules more like those of 0. pumilum Sw. 



12. Orthotrichum stramineum Hornsch. (Tab. XXXV. J.). 



In yellowish- green or bright green tufts, resembling O. affine. 

 Leaves resembling those of that species. Capsule more or less 

 emergent, rather short, yellowish brown, oblong-elliptic, quickly 

 contracted into a short neck, about half the length of the capsule, 

 with 8 prominent ribs, of 2-5 rows of strongly incrassate cells ; 

 when ripe and open constricted just below the narrow mouth, then 

 quickly widening again ; peristome teeth in 8 pairs, yellow, reflexed 

 when dry, papillose, processes 8, more rarely 16 ; stomata immersed, 

 almost closed by the very swollen, elevated overlapping cells; 

 calyptra pale yellow with a darker point, slightly hairy. Vaginula 

 very hairy. Autoicous. 



Var. p. patens Vent. (Orth. patens Bruch, Schp. Syn.). Ribs 

 of capsule much fainter , of 2 rows of less incrassate cells. 



Hab. Trees, rarely on rocks ; not uncommon in mountainous districts. The 

 var. (3 rare. Fr. summer. 



There is no difficulty in recognising this species, under the microscope, from 0. 

 ajjine, the very hairy vaginula and immersed stomata at once distinguishing it ; in the 

 field there is more resemblance, but the straw coloured calyptra, and the small but 

 rather wide, yellowish capsule, small at the mouth and usually rather constricted below 

 it, with very distinct ribs, is sufficient to identify it as a rule ; old capsules, however, 

 differ less. O. tenellum has a narrower, brighter coloured capsule, with a more taper- 

 ing neck. 



13. Orthotrichum tenellum Bruch (Tab. XXXV. K.). 



In short, dark green tufts about £-inch high. Leaves erecto- 

 patent, erect and imbricated when dry, short, narrow, lanceolate 



