10 SPHAGNACE/E. 



with the extremely narrow margin of the stem leaves, and their greater size and width ; 

 but there are forms of S. acutifolium with fibrillose and narrowly margined leaves ; 

 in these cases the colour, the less acute and more abruptly truncate branch leaves 

 in S. molle, taken together, will form a combination of characters probably not to be 

 found in any of the forms of that species. The few and scattered pores in the branch 

 leaves will serve to separate S. molle from 5. subsecundum. The var. tenerum may 

 easily be confounded with the compact form of S. acutifolium, but under the 

 microscope the resemblance will probably disappear. The difference between this 

 var. and 5. rigidum has been pointed out already under that species. 



The stem leaves in S. molle are usually, but not quite always, broader in the 

 middle than at the base. The margin is sometimes reduced so as to be very indis- 

 tinct, but is sometimes very clear, and occasionally widened out below. 



C. SUBSECUNDA. 



Cuticular cells of stem without fibres or pores. Stem leaves 

 bordered with narrow cells. Branch leaves usually subsecund, 

 more or less oval, at apex rounded or truncate, and toothed. 

 Branches often curved. Dioicous. 



5. Sphagnum tenellum Ehrh. (S. molluscum Bruch, Schp. 

 Syn.) (Tab. VI. F.) 



Plants rather densely tufted, 2-6 inches high, very slender 

 and fragile, greenish yellow. Stem pale, cuticular cells in two 

 layers. Stem leaves rather large for the size of the plant, oval- 

 oblong ; rounded above with the margin incurved, and with a few 

 small teeth at the apex ; upper median cells fibrose with a few 

 small pores, the basal ones much narrower, and passing insensibly 

 into the very broad border of narrow marginal ones, which, how- 

 ever, becomes narrower as it reaches higher up the leaf, until at 

 the apex it consists only of two or three rows of narrow linear 

 cells. Branches short, the retort cells much recurved at apex ; 

 leaves somewhat loosely set, often subsecund, broad and short, 

 widely ovate and ovate-oblong, obtusely pointed, concave, margin 

 incurved above, apex 3-5 toothed; bordered with a somwhat broad 

 margin of linear cells, in 3-4 rows. Hyaline cells small, but 

 broad, with numerous rather small pores on the ventral surface. 

 Chlorophyllose cells triangular in section, on the dorsal ia.ce of the 

 leaf. Capsule thin walled. 

 Hab. Bogs. Frequent. 



Sphagnum tenellum is the smallest and most delicate of our species, and is 

 hardly likely to be confounded with any other, the broadly oval leaves serving to 

 distinguish it from slender forms of the Acutifolia group ; while the strongly recurved 

 apex of the retort cells, and the much shorter and broader hyaline cells of the branch 

 leaves will serve to separate it from small varieties of .S. subsecundum, and from S. 

 molle var. tenerum. 



Braithwaite records var. longifolium Lindb., but it does not appear to be a 

 strongly marked form. 



