BARBULA. 199 



11. Barbula Hornschuchiana Schultz. (Tab. XXIX. M.). 



Pale green, in low tufts or patches, about £-inch high. Stems 

 slender ; leaves spreading, when dry rigidly arcuate-incurved 

 and spirally twisted ; very small, rather larger at the top of 

 the stem, ovate-lanceolate or narrowly triangular, gradually 

 acuminate from the base or just above to an acute point, sharply 

 mucronate or cuspidate with the stout, yellowish, excurrent nerve ; 

 margin very widely and strongly revolute in its whole length, 

 reaching to or almost to the nerve in the upper half of the leaf ; 

 upper cells rounded-quadrate, distinct, incrassate, obtusely 

 papillose, at base very shortly rectangular, rounded at angles, 

 rather incrassate. Perichaetial bracts larger, longer, sheathing, 

 with plane margins, longly acuminate, with narrower nerve. Seta 

 orange red below, pale above ; capsule small, narrowly elliptic or 

 sub-cylindric ; lid long-beaked ; peristome teeth from a very 

 narrow membrane, rather long, purple, much twisted. Dioicous. 



Hab. On the ground in fields, old quarries, and on walls ; not common. Fr. 

 spring. 



This and the two following species have a certain affinity and are distinguished by 

 their small size, much smaller leaves, paler seta and more highly differentiated 

 perichaetial bracts from the other species of the genus. The present plant may easily 

 be overlooked as a small state of B. fallax or some other moss, but it is recognised 

 almost at a glance by the stellately-spreading small tapering acutely pointed leaves 

 with strongly revolute margins ; B. revoluta has the leaves much less tapering, more 

 linear and obtuse at the point. 



12. Barbula revoluta Brid. (Tortula revoluta Schrad.) 



(Tab. XXX. A.). 



In very dense, low, smooth tufts or cushions, bright or dull 

 green, \-\ inch high, rarely taller. Leaves crowded, erecto-patent 

 or spreading, slightly recurved, closely and very neatly curled 

 when dry, very small, ligulate-oblong from a rather broader 

 base, scarcely tapering above, at apex rather obtuse and apiculate ; 

 margin very widely and strongly revolute from just above base to 

 apex, reaching almost to the nerve in the whole of the upper part ; 

 nerve very thick, and wider above than in the lower half, usually 

 excurrent in a small mucro or apiculus ; cells rounded-quadrate, 

 obscure, papillose, at base rectangular, pellucid ; all rather 

 incrassate, rounded at the angles. Perichaetial bracts much 

 longer than the leaves, sheathing. Seta orange, paler above, 

 slender, twisted to the right when dry ; capsule elliptical, lid 

 rather short ; peristome much twisted. Dioicous. 



