MOSS HABITATS. 33 



orbicularis, Ditrichum flexicaule, Pottia lanceolate Mnium 

 stellare^ Trichostomum tophaceum^ Bartramia calcarea, etc. 



The Seligerias are minute species, most likely to be found 

 on jutfmg*"focks in calcareous districts, and possibly the 

 species most frequent will be S. pusilla, which will be found 

 growing in light-green patches. As it is a very minute 

 species, only close observation will detect it. Usually it 

 occurs in fairly dense masses, and may be recognised by 

 its small, awl-shaped leaves, straight fruit-stalk, and small, 

 top-shaped capsule. It will be in fruit in April or May. ^ 

 Another- very characteristic calcicolous moss is Eucladium 

 vertidllatum, which appears to favour moist rocks among 

 trickling water, and usually the stems will be found more or 

 less encrusted with a calcareous deposit. The stems vary 

 from half an inch to two inches in height, and it occurs in 

 dense, pale, bright-green tufts. Although this moss really 

 belongs to the acrocarpous or terminal-fruited section, it 

 may appear to the novice to be a lateral-fruited species, 

 owing to the lateral prolongation of the branches. The 

 leaves are narrow, rigid, and strongly nerved. Capsule 

 erect, oval, glossy, reddish; peristome simple, of sixteen 

 teeth ; fruit ripe in June. It may be mentioned, in passing, 

 that when this or any other calcicolous species is intended 

 to be mounted in glycerine or any glycerine compound, it 

 should be first of all soaked for a short time in dilute nitric 

 acid, to dissolve the calcareous matter adhering to the stem, 

 and then well washed in water, otherwise the chalky par- 

 ticles will effervesce in the glycerine, and so spoil the pre- 

 paration. Encalypta vulgaris will also occur on these 

 banks, and this species will be readily known by its large, 

 pale-green, extinguisher-like calyptra (fig. n, 2), which 

 covers the whole capsule, the large leaves, twisted when 

 dry, and cylindrical capsules. It will be found in fruit in 

 April, and may be known from other species of the same 

 genus by the calyptra being entire at the base. In the other 

 species, the calyptra is always toothed or fringed at the 

 base, with fine, hair-like processes. Grimmia orbicularis 

 should also be sought in such districts, but may be looked 

 for on calcareous rocks rather than banks (fig. 19, 4). It 



D 



