106 DICRANACEyE. 



closely than any species of its own genus, but the strongly undulate leaves will 

 distinguish it in the field, and under the microscope the auricles, the elongated basal 

 cells, and the non-papillose upper ones will readily determine it. 



Not only are the leaves of D. Bergeri actually broader at the points than in the 

 allied species, but this feature is the more conspicuous from the fact that they are less 

 convolute or tubular, both when moist and in the dry state. 



Both this and the last species have the nerve at back markedly yellow and shining 

 in the upper leaves when dry. 



D. Bergeri is sometimes found with short, dwarf, compact stems (var. compactum 

 Ren. & Card. ) ; and there is also, as in the last, some variation in the amount of 

 denticulation of the leaf-margin. I have received forms from North America with 

 short narrow leaves, and with the cells more or less elongated and large even to the 

 apex ; it can then only be separated from D. Bonjeani by the non-porose upper cells, 

 which are shorter than in that plant. 



9. Dicranum Bonjeani De Not. (D. palustre B. & S., Schp. 

 Syn.) (Tab. XVIII. B.). 



In its typical form the species grows in close tufts of a pale 

 fawn or light green colour, more slender than D. scoparium, with 

 the leaves erecto-patent or only very slightly secund, straight 

 and appressed when dry, often in interrupted tufts, shorter (2-3 

 lines), and less narrowly acuminate above, with a broad point, 

 transversely undulate when moist, distinctly serrate on the 

 borders, less concave, the nerve smooth or faintly serrate at the 

 back, very narrow at base, the upper areolation rather shorter 

 and wider, irregularly hexagonal-elliptic. Seta solitary, paler, 

 rather more slender ; capsule very similar, but shorter and 

 usually lightly striate, rather paler. Habit somewhat of Campy- 

 lopus flexuosus var. uliginosus, but more robust, and with the 

 upper leaves forming a more or less distinct coma. Male flower 

 usually on a separate plant. 



Var. p. juniperifolium Braithw. Leaves broader, rigid, 

 erect, straight, brownish. 



Var. y. calcareum Braithw. Shorter, more rigid ; leaves 

 secund, sub-falcate, concave, and sub-tubular above, undulate 

 only at apex, and slightly serrate only towards point. 



Hab. In marshes and on heaths in shady places. Common. Var. fi less 

 common ; var. y on chalk hills, rare. Fruit rare, late summer. 



Besides the above varieties, D. Bonjeani presents many other less distinct or less 

 widely spread and hence unnamed forms ; it occurs with long, flexuose stems and 

 distant, bright green, strongly falcate leaves, resembling slender states of the next 

 species ; sometimes it is very tall and robust, 4-6 inches high, with densely packed 

 leaves ; the latter vary greatly in length, form, and amount of serrature and undula- 

 tion ; a form occurs in bogs with long narrow leaves, the whole of the blade strongly 

 undulated, remaining rugose when dry, and reminding us of D. undulatum. I have 

 also found a form in Cornwall, with slender stems and small, short, distant, falcate 

 leaves, presenting an appearance like that of the most slender forms of D. fiiscescens. 



