DICRANODONTIUM. 99 



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25. DICRANODONTIUM B. & S. 



Stems slender, tomentose ; leaves setaceous, with a broad 

 nerve. Capsule symmetrical, on a flexuose curved seta ; calyptra 

 entire at base ; peristome teeth cleft to base into two sub-equal, 

 subulate divisions, remotely articulate. 



Somewhat intermediate between Campylopus and Dicranum, 

 with the habit and entire calyptra of the latter genus, but with 

 the deciduous leaves, the capsule and broad nerve of the former ; 

 differing from both in the peristome. 



Dicranodontium longirostre B. & S. (Didymodon denudatus 

 Lindb., Braithw. Br. M. Fl.) (Tab. XVII. A.). 



In soft, silky pale green tufts, with slender flexuose radiculose 

 stems ; leaves easily deciduous, flexuose-spreading or falcato- 

 secund, from a semi-sheathing convolute base gradually narrowed 

 to a flexuose, very finely setaceous point, tubular above ; margin 

 involute, sub-entire or faintly denticulate near the apex ; nerve 

 §-| width of base, excurrent at apex in a rough point, thick, 

 prominent at back, in section of several rows of minute incrassate 

 cells with a single median row of larger hyaline ones. Auricles 

 large, inflated, distinctly wider than the leaf base, hyaline or 

 reddish brown ; basal cells rectangular, upper narrowly elliptic, 

 or rectangular-rhomboid. Seta cygneous, capsule small, cylindric; 

 lid straight, subulate, as long as capsule. Peristome pale red. 

 Dioicous. 



Var. ji. alpinum (Schp.) (Campylopus alpinus B. & S.) 

 Taller, more robust ; leaves not deciduous, firmer, usually more 

 erect. 



Hab. Banks and rotten wood in mountainous districts ; not common. The 

 var. j8 in grassy places on mountains, rare. 



Somewhat resembling Ditrichum fiexicaule, but with more divergent, flexuose 

 leaves, which differ entirely under the microscope in the large auricles ; the Ditrichum 

 too is almost confined to calcareous rocks. 



The var. & resembles certain species of Dicranum ; but the form of the leaf base 

 and its areolation will separate it with ease from most of them ; D. asfierulum has a 

 rougher subula and both it and D. longifolium have a very different nerve section. 



26. DICRANUM Hedw. 



Plants varying in size, often tall and robust ; leaves often 

 falcato-secund, smooth or papillose, lanceolate or lanceolate- 

 subulate, elongated ; nerve usually narrower, sometimes dilated ; 



