SPHAGNUM. 15 



ling S. cymbifolium in robustness. Cuticular cells of stem in two 

 layers. Leaves of divergent branches strongly squarrose from the 

 middle in the lower two-thirds of the branch, in the upper third 

 imbricate and terete ; their form as in 5. teres, but much larger, 

 the hyaline cells somewhat larger also. Male amentula clavate, 

 rarely attenuated. Monoicous or dioicious. 



Var. /3. imbricatum Schp. Robust. Branch leaves more 

 or less imbricated. 



Hab. Bogs, frequent. 



Dr. Braithwaite in his splendid work on the Sphagnacea? has clearly shown 

 that 5. teres cannot be separated as a species from S. squarrosum. I have followed 

 Cardot, however, in subordinating the latter to the former, as a sub-species, instead of 

 making J 1 , teres a variety or sub-species of S. squarrosum, fully concurring in his 

 reasons for so doing. Squarrose-leaved forms must be considered as diverging from 

 the more normal, imbricated forms, and not vice versd ; it is on precisely the same 

 principle that the contortum forms of S. subsecundum are looked upon as secondary 

 to the type of that species, the var. sedoides to S. Pylaiei, and the var. compactum to 

 S. rigidum. The fact that the squarrosum forms are more robust than those of S. teres 

 is of course no argument against this view, as precisely the same is the case with the 

 vars. contortum and obesum of J. subsecundum, and the var. riparium of ^. inter- 

 medium. 



S. squarrosum is united with 5. teres by an almost unbroken series of forms through 

 the var. squarrosulum. The var. subteres differs from the type in scarcely anything 

 but the more slender build and the slightly more recurved leaves ; intermediate forms 

 connect this variety with the type, and the same is the case with 5. squarrosum and 

 its var. imbricatum, which are united by all possible shades of transitional forms. 

 The extreme form of the latter, with the leaves all imbricated and not squarrose, 

 would appear to be very rare. 



S. squarrosum can hardly be confused with any other species ; the var. 

 squarrosulum of 5. cymbifolium might at first sight be sometimes taken for it, but the 

 acute branch leaves of S. squarrosum will, on closer examination, make the distinction 

 manifest at once. It is somewhat different with S. teres, forms of which might easily 

 be taken for some others of the Acutifolia section, but the form of the stem leaves, 

 rounded at the summit and not distinctly larger above than at the base, and 

 especially their very narrow margin, not widened at the base, will always reveal their 

 identity. The var. laxum was at first described by Braithwaite as .S. fimbriatum var. 

 robustum, and the broad, strongly fimbriate stem leaves are very suggestive of this 

 species ; I find, however, some of the stem leaves exactly typical of S. teres, while 

 others in abnormal stems have both the form and areolation of branch leaves of S. 

 squarrosum, but a little more obtuse ; and, moreover, the margin of narrow cells, 

 though slightly broader at base, never passes into the very broad, dense column of 

 linear cells so marked in 5. fimbriatum. 



8. Sphagnum acutifolium Ehrh. (Tab. VII. E.). 



Tufts soft, pink, pale green, or whitish, but always with 

 some admixture of red (in very rare cases confined to the male 

 amentula), 3-12 inches high. Stem generally reddish, some- 

 times green, cuticular cells with or usually without pores. Stem 

 leaves very variable, usually small, oval-triangular, gradually or 

 abruptly narrowed to an obtuse point, with about 5 teeth ; some- 



