SPHAGNUM. 17 



** Vars. brown, yellowish, or whitish. 



f Branch leaves short, oval, more or less obtuse. 

 Var. 1. fuscum Schp. Bright yellowish brown above, 

 fuscous below ; slender, in dense cushions. Stems dark brown, 

 branches short. 



Var. k. arctum Braithw. Very compact and short, fragile. 

 Pale yellow above, whitish brown below. Branches very short, 

 densely crowded, ascending. 



ft Branch leaves ovate-lanceolate, elongated. 

 Var. A. luridum Hub. (forma stricta Warnst.) Stem leaves 

 large, elongate, oblong, suddenly narrowed to a point. Branches 

 short, closely set, ascending. Tufts dense, of a dirty brownish 

 green colour. 



Var. /j. patulum Schp. Stem leaves oblong-lingulate, 

 more or less narrowed above but truncate. Branches lax, leaves 

 loosely imbricated. Pale green, rather tall and robust. 



Var. v. Isete-virens Braithw. Branches laxly set ; leaves 

 loosely imbricated, broadly ovate below, suddenly narrowed to an 

 elongated point. In small dense cushions, bright green above, 

 pale below. 



Hab. Bogs and pools. Very common. 



S. acutifolium is the most variable of all the species. The varieties are so 

 endless, and so complex in character, as almost to defy classification. Almost every 

 writer on the genus has his own system and his own nomenclature ; and since different 

 authors base their systems on such different characters as the form of the stem leaves, 

 the form and arrangement of the branch leaves, the arrangement of the pores in the 

 hyaline cells, etc. , any attempt to collate these various forms is frustrated by the over- 

 lapping of the groups. When it is stated that Russow and Warnstorf alone describe 

 far more than 50 forms, Cardot above 30 European forms, only a part of these 

 corresponding to the former ones, and so on with other authors, some idea will be 

 formed of the great number of varieties and the difficulty of treating them. I have 

 endeavoured in the first place to select only the most clearly marked forms among 

 the British varieties, and in the second place to arrange them less with a view to a 

 natural classification than with the hope of rendering their identification — so far as 

 identification of varieties is possible by description alone — as easy as possible. 



The var. rubellum has been often considered a separate species, and has some 

 right to be placed as a sub-species, but hardly more so than the vars. fuscum, luridum 

 and quinquefarium. Hobkirk ( ' Syn. , Ed. 2) places it under the section Subsecunda, 

 with which it has some relationship ; and if it stood alone in the form of leaf, its 

 removal from the section Acutifolia would leave that group a very natural one in the 

 .ovate-lanceolate and acuminate leaves ; but as so many of the other varieties have 

 similarly shaped leaves, while their affinities with 5. acutifolium are undoubted, the 

 removal of ^. rubellum alone in no way improves the general classification, while its 

 relationship to 5. acutifolium in other respects can hardly be questioned. 



The vars. fuscum Schp. and luridum Hub. comprise each a considerable 

 variety of forms, chiefly varying'in size and habit of growth ; the plant described and 

 figured by Braithwaite under the latter name would appear to be the forma stricta of 

 Warnstorf. 



