248 The JJicranums, or Fork-Mosses. 



THE DICRANUMS, OR FORK-MOSSES. 



BY M. G. CAMPBELL. 



About thirty species of Fork-moss are ascertained to be natives 

 of the British isles. These, by strongly marked distinctions 

 of foliage, naturally divide themselves into two groups, with 

 the generic appellations of Dicranum and Fissidens. 



As six of the Dicranums are in fruit during the month of 

 November, we will confine our attention to them for the 

 present. They are named from hUpavGv, a forked instru- 

 ment, in allusion to the cloven teeth of the genus, and are 

 perennial plants, growing on rocks or on the ground, some- 

 times on the trunks of trees, in tufts more or less dense 

 and extensive ; the stems varying in height from a few lines to 

 several inches; the smaller species not much unlike the 

 Weissise ; the larger, among which are some scarcely surpassed 

 in size by any other of the acrocarpous division of mosses, in 

 some instances bear considerable resemblance to the Trichos- 

 toma and Gynodontium. The leaves are usually somewhat 

 lanceolate, spreading, or secund, i.e., all turned to one side, 

 the reticulation variable, usually small, dot-like or roundish in 

 the narrower part of the leaf, elongated, narrow, and often 

 wavy lower down, at the marginal base considerably enlarged, 

 quadrate, and tinged with colour more or less deeply. The 

 calyptra cucullate, with a long beak ; the lid conical at the base, 

 with a long beak, slender oblique, and varying in length. The 

 peristome single, consisting of sixteen equi-distant teeth, which 



are -confluent at the base, and cloven half 

 way or more into two unequal portions, 

 the medial line being continued to the 

 base with occasional perforations. They 

 are also marked with transverse bars, 

 prominent on the inside of the tooth, and 

 surrounded externally with a somewhat 

 rigid membrane of a red or orange colour. 

 The spores are rather small and of a red- 

 dish brown tint. 



The most commonly met with is Dicra- 

 num heteromallum, or the Silky-leaved 

 Fork-moss. It grows in^ extensive silky 

 patches upon moist banks, the stems 

 tufted, or matted together, simple or 

 branched, with crowded secund leaves, 

 somewhat bristle- shaped and slightly den- 

 tate at the apex, of a silky appearance and with a flattened nerve, 

 which forms the chief part of the upper portion of the leaf, giving 



