DICRANUM. 107 



On the whole, however, it is not a difficult plant to distinguish. The short 

 leaves with broad points, less serrate at back, the rather wider and more pellucid 

 areolation, and the more or less strongly undulated leaves are characters one or more 

 of which will always be found, and in practice the only plant with which there is likely 

 to be any confusion is the var. paludosum of the next species, which, however, almost 

 always has longer, narrower, linear-subulate points and nerve serrated at back. The 

 habit and the upper areolation separate it easily from D. Bergeri. It varies much in 

 colour, being sometimes almost black below. 



The fruit is much more rare than that of D. scoparium, but I have found it in 

 several localities in the south of England. In North America the fruit would appear 

 to be not at all uncommon. The name palustre by which it is often known, but 

 which should give place to the earlier name, is fairly appropriate, but the plant is by 

 no means confined to marshy ground. I have found it growing abundantly on the 

 thatched roof of a church in Suffolk ! 



Hobkirk {Synopsis) describes a var. — rugifolium Boswell — (perhaps only a form) 

 with the leaves somewhat contorted and crisped and more strongly undulate ; I have 

 seen no specimens, but I have plants from several localities, usually distinctly paludal, 

 with the elongated leaves very strongly rugose when dry as well as when moist for the 

 whole length of the leaf, not merely in the upper part ; they seem quite deserving a 

 varietal name, but I cannot certainly refer them to the above var. in the absence of 

 authentic specimens, especially as the terms contorted and crisped are hardly applic- 

 able to the leaves of the plants in question. 



10. Dicranum scoparium Hedw. (Bryum scoparium L.) 



(Tab. XVIII. C). 



A very variable species, in its typical form somewhat 

 resembling D. majus, but smaller, more densely tufted, the 

 leaves shorter (2^-4 lines), more crowded,, often in interrupted 

 tufts, less regularly falcate, sometimes erecto-patent, but almost 

 always more or less turned to one side, glossy yellowish green, 

 narrower at base, less concave, not, or very rarely, undulate, 

 slightly flexuose at the point when dry, the subula broader and 

 shorter, the nerve slightly narrower at base, with four ridges at 

 back above, which, with the margins, are usually serrate ; lowest 

 basal cells rather laxer, rectangular, with thinner walls, the 

 upper rather wider, the marginal cells in the upper part usually 

 pellucid, forming close but less acute serratures ; cell walls all 

 porose, the contents more distinctly chlorophyllose, often, in the 

 younger, active leaves, mixed with oil globules. Seta solitary, 

 reddish, rather stouter ; capsule cernuous, arcuate-cylindric, 

 rufescent, not striate, with a distinct but not strumose ,neck ; lid 

 with a stouter beak. 



Var. /3. paludosum Schp. Tall, bright green, usually very 

 white with tomentum; leaves secund, hardly falcate, sharply 

 toothed, transversely undulate near apex. In boggy places. 



Var. y. orthophyllum Brid. In dense tufts ; leaves erect, 

 spreading equally or slightly secund, subula narrow, distinctly 

 toothed. 



