SPHAGNUM. 13 



Var. p. platyphyllum Lindb. Stems short, the leaves dis- 

 tinctly auricled. Branches short, rather obtuse, with imbricated 

 leaves which are rounded ovate, pointed, very broad and concave. 



Var. 7. cyclophyllum Lindb. (S. cyclophyllum Sull. & Lesq.) 

 Stems simple or nearly so. Stem leaves very large, orbicular, 

 cucullate. 



Hab. Deep bogs. It appears to be a much rarer plant than 5. subsecundum, 

 for which, however, it may frequently have been mistaken. The var. fl in peaty 

 places, among short grass. Near Aber ; Scotland. The var. 7 very rare ; Loch 

 Katrine. 



The character drawn from the perichaetial bracts may be of importance, should 

 it prove to be constant. As to the other points, there is a great discrepancy between 

 authors as to the number of pores in the hyaline cells ; thus Hobkirk (Synopsis, Ed. 

 2, p. 49) says, " Cells with annular fibres and many pores"; Russow and Warnstorf, 

 " Pores on back of leaf isolated or numerous " ; while in specimens of Gravet's which 

 I have examined the pores at the back of the leaf are as numerous and regular as, if 

 smaller and less conspicuous than in S. subsecundum. In this latter species, too, it is 

 not unfrequently the case that the pores are less regular and less numerous than in the 

 type. There remains the character derived from the cuticular layers of the stem. In 

 the species in which these cells occupy " from 2 to 3 layers" it is questionable whether 

 if certain plants had them constantly in 2, and others constantly in 3 layers, this would, 

 in the absence of other striking characters, be held sufficient to separate them as 

 species. In point of fact, although in .S'. squarrosum these cells are in 2 layers, 

 while in .S. teres they are usually in 3 or 4, their separation as distinct species is 

 not felt by authors (Braithwaite, Lindberg, &c. ) to be thereby rendered necessary. 

 And if so we may venture to ask where the radical difference lies when it is a question 

 of 1 as against 2 (or sometimes 3) layers of cells. There seems too the less reason for 

 insisting on this distinction, since Cardot affirms (les Sphaignes cC Europe, 1886, p. 55) 

 that he has several times examined specimens of S. laricinum in which the second 

 stratum of cells has been incompletely developed. 



I have therefore followed the latter author, though with some hesitation, in con- 

 sidering S. laricinum as a sub-species of .S. subsecundum. This view is distinctly 

 supported, moreover, by the fact that the variations of 6 1 . laricinum are almost 

 exactly parallel to those of ^. subsecundum, — the var. teretiusculum Lindb. agreeing 

 exactly with the var. contortu?n of that species, the var. platyphyllum Lindb. with 6". 

 subsecundum var. viride Boul. (or var. auriculatum Lindb. ) The var. cyclophyllum 

 Lindb. , by some authors, and subsequently by Lindberg himself considered a species, 

 is said also by Braithwaite to correspond with the var. obestim Wils. of the former. 

 There seems to be considerable difference of opinion about this variety, which, 

 according to Lesquereux and James (Mosses of North America, p. 22) is allied to 8. 

 subsecundum rather than to S. laricinum, as it is described with "cortical cells in 

 a single layer." It has very large roundish stem leaves, concave and cucullate, and 

 the stems are frequently simple, or with very few, short, obtuse branches. 



D. ACUTIFOLIA. 



Usually slender. Cuticular cells of stem not fibrose, some- 

 times porose. Stem leaves bordered. Branch leaves ovate- 

 lanceolate or lanceolate, (rarely shortly ovate and obtuse), acute 

 or narrowly acuminate, narrowly truncate and toothed at apex. 



