68 THE SPHAGNA CEsE OP PEAT-MOSSES OF 



The typical state of Sph. acutifolium is that termed robustum by 

 Blandow and Nees and Hornschuch, in which the stems are stout 

 and often tall, the branches rather short, thick, and glossy, with 

 leaves more or less tinted with red. So much, however, does the 

 plant vary in size, colour, and density, and in the form of both the 

 stem leaves and branch leaves, that an endless series of forms 

 result, the transitions between which are so gradual that it becomes 

 difficult to keep the varieties within definite bounds. Schliephacke 

 pointed out an important character in the structure of the branch 

 leaves, viz. that the divergent branches bear up to the middle, 

 leaves whose lower wider cells have single large pores, these cells 

 becoming towards the point very small, closely and equally small- 

 pored ; but as the leaves rise higher on the branches, they gradually 

 pass to a lanceolate or lanceolate-subulate form, and the areolation 

 then becomes uniform throughout the leaf, wider, laxer, and pro- 

 vided with equal large pores. 



The apex of the stem leaves in the robust form is often some- 

 what truncate and slightly fringed, and thus may be easily mistaken 

 for Sph. strictum, as was the case in my Exsiccata, under n. 42 b 

 (var. subfmbriatum) ; but Sph. acutifolium may be known from 

 that species by its red amentula, and softer, laxer branch leaves ; 

 in other forms the point is obtusely rounded, with small imperfect 

 teeth, or again the teeth may be distinct and well defined. 



The stem leaves also vary considerably in form and size ; occa- 

 sionally we find them very long and ligulate-lanceolate in outline, 

 or they may pass to the opposite extreme and be short and broadly 

 ovate, but unfortunately these differences are not always asso- 

 ciated with the same conditions of habit and colour, and thus a 

 sharply defined limit to the numerous varieties of this species 

 appears to be impossible. 



Var. /3. deflexum, Schimp. 



Plants densely tufted, short, with closely placed fascicles. 

 Branches long, flagelliform, all deflexed, their leaves closely imbri- 

 cated, longer and narrower, pale green and red. Stem leaves 

 ovate, pointed, mostly fibrillose. Branch leaves lanceolate, 

 acuminate. 



Synon. — Sph. acutifolium var. /3. deflcxum, Schimp. Torfm. p. 57, t. xiii. £; 

 Synops. p. 673, et ed. 2, p. 826. Russow, Beitr. p. 39 (including also his var. 

 laxum). Milde, Bry. Siles. p. 381. Klinggr. in Schr. der K. Phys. CEk. Gesel. 

 zu Konigs. 1872, p. 3. Braithw. Sphag. Brit. Exsic. n. 32. 



