182 TORTULACE/E. 



The texture of this species is remarkably soft and delicate, and from its wide 

 leaves with lax smooth areolation it cannot be taken for any other species of the genus. 

 The leaves are frequently almost as broad as long, but are variable in form and degree 

 of obtuseness. They are not unlike some of the broad-leaved species of Pottia, such 

 as P. Wilsoni and P. viiidifolia, but these are almost always smaller and narrower, 

 and have papillose areolation and recurved margins. 



10 Tortula Vahliana Wils. Barbula Vahliana Schultz., 

 Schp. Syn.) (Tab. XXVII. H.). 



Stems short, gregarious, pale green; resembling T. muralis 

 var. sestiva. Leaves patent, soft, erect and slightly twisted when 

 dry, oblong-lingulate , obtuse or slightly acute, thin ; margin plane 

 or here and there lightly recurved, very rough with projecting 

 double papillae; nerve thin, excurrent in a short point or long 

 greenish arista; cells rectangular and hyaline at base, rounded- 

 hexagonal above and opaque with chlorophyll and papillse, 1-2 

 rows at margin more pellucid, forming a faint border. Capsule 

 longly cylindrical, on a dark red seta, slightly curved ; lid shortly 

 rostellate, \ length of capsule ; annulus broad ; peristome long, 

 twisted, from a short but distinct basal membrane. Autoicous. 



Var. /3. subflaccida Lindb. (T. dblongifolia Wils.). Smaller, 

 leaves shorter, more opaque, margin plane, nerve shortly 

 excurrent; capsule and lid shorter. 



Hab. Banks, usually on calcareous soil ; very rare. Sussex ; Cambridgeshire ; 

 Herefordshire. The var. near Dublin. Fr. spring. 



Although very much resembling some forms of T. muralis, especially the var. 

 astiva, there is not likely to be much difficulty in identifying the present species, the 

 habitat and mode of growth being quite different from the tufted or densely crowded, 

 rupestral habit of that moss ; the leaves too are broader and thinner, with the margin 

 less strongly and regularly revolute, and the capsule more elongate. As in the last 

 species, the leaves are subject to much variation in form, and the hair-point is variable 

 in length. Like T. cwtetfolia it is a southern, indeed a Mediterranean species. 



11. Tortula marginata Spruce. (Barbula marginata 

 B. & S, Schp. Syn.) (Tab. XXVII. I.). 



Short, densely gregarious or in wide patches ; pale or dark 

 green above, brown below. Leaves erecto-patent, when dry very 

 slightly twisted, narrowly oblong or Ungulate, sub-acute, rarely 

 obtuse ; margin plane, bordered with a distinct yellowish band of 

 2-4 rows of linear cells in two layers, paler than the rest of the 

 leaf, nerve excurrent in a short green mucro ; upper cells small 

 and dense, sub-quadrate, very opaque and obscure, papillose. 

 Seta bright orange red, slender ; capsule oblong-cylindric or 

 shortly cylindric ; lid about \ length of capsule; peristome on a 

 short basal membrane. Dioicous. 



