BARBULA. 195 



them strongly recurved, and so on ; but in B. recurvifolia the characters above 

 described form a general facies which is hardly to be found in any form of true B. 

 fallax. The vinous red colour, slender stems, and short recurved leaves will render 

 this plant easily recognised, but it should always be verified with the microscope. 

 The fruit is extremely rare, and has, perhaps, not been found in Britain. 



5. Barbula spadicea Mitt. (Trichostomum rigidulum Sm. 

 pro parte). (Tab. XXIX. F.). 



Resembling B. fallax, but more robust, dull green, brown 

 below. Leaves erecto-patent, straight, rarely spreading or 

 recurved, from a broad base gradually narrowed to a broad, 

 usually hardly acute point; nerve strong, wide at base; cells 

 small, angular, usually irregular, sub-hexagonal, rather obscure ; 

 hardly altered at base except a very few of the lowest. Seta 

 and capsule as in B . fallax ; lid shorter, peristome much shorter, 

 the teeth hardly twisted, filiform, from a narrow basal membrane. 



Hab. Wet rocks and sandy shores of mountain streams ; not common. Fr. 

 late autumn. 



Although in its peristome resembling B. tophacea or B. rigidula, and on that 

 account long united with the latter, the affinity of this species is closest with B. fallax, 

 from which it is very difficult, if not impossible, always to separate barren plants. It 

 has been suggested that the cells in the present plant, irregularly angular, afford a 

 distinguishing character, those of B. fallax being more distinct, rounder, and more 

 regularly seriate, but although this frequently holds good, I have examined specimens 

 of undoubted B. fallax with precisely the areolation typical of the present species. 

 The leaves in B. spadicea, again, are sometimes said to be straight and appressed when 

 dry, not twisted as in B. fallax, but this is undoubtedly an error. According to my own 

 observation the most useful character is the direction of the leaves when moist, 

 straight and erecto-patent in B. spadicea, very rarely flexuose or recurved as is 

 frequently the case in B. fallax. They are, too, always broad at the points, but the 

 same may be observed, frequently though not usually, in the latter species. 



B. rigidula differs in the smaller, narrower-pointed leaves, with more elongated 

 basal areolation. 



6. Barbula rigidula Mitt. (Didymodon rigidulus Hedw. ; 



Trichostomum rigidulum var. densum B. & S., plur. auct.) 



(Tab. XXIX. G.). 



Growing in small dense tufts or cushions, rarely 1 inch high, 

 dull or yellowish green above, reddish brown below. Leaves 

 rather crowded, resembling those of B. fallax but rather wider 

 and shorter, more narrowly acuminate to a straight almost linear 

 point; straighter and less recurved, more concave, hardly 

 papillose. Margin recurved below, slightly thickened above ; 

 nerve brown, lost in the rather opaque point. Areolation small, 

 dense, rounded-hexagonal, rather obscure in the point, more 

 distinct below, faintly papillose, towards base becoming quadrate 



