HETEROCLADIUM. 379 



An extremely variable species ; the var. /3 is one of the most slender of our 

 mosses, resembling A?nblystegium Sprucei, and hardly to be known from some slender 

 species of that genus except by the papillose cells, which are much shorter in the 

 middle of the leaf in the variety than in the typical plant ; indeed one would be 

 inclined to attribute to it a higher than varietal rank were it not that intermediate 

 forms occur ; I have gathered one which showed a few branches with almost typical 

 leaves, while the greater part of the plant was clearly referable to the variety. 



On the other hand, luxuriant forms have large, acuminate leaves, usually more or 

 less distichously arranged in two rows drooping on either side of the stem, and bear a 

 resemblance to Pterigynandrum filiforme-mx. heteropterum, but have the leaves much. 

 more distant than is usual in that plant. In these forms it approaches nearer the 

 next species, but the acumen of the stem-leaves is never squarrose-recurved as in 

 that. 



2. Heterocladium squarrosulum Lindb. (Hypnum squar- 

 rosulum Voit ; Heterocladium dimorphum B. & S., Schp. Syn.) 



(Tab. L. N.)- 



Closely resembling the last species ; stem-leaves distant, 

 widely cordate-ovate, rapidly contracted to a long, flexuose, 

 almost filiform acumen, which is squarrose-recurved, irregularly 

 denticulate ; all median cells and those of the acumen linear, 

 6-10 times as long as wide, smooth, towards margin (in the 

 widest part) in several rows short, sub-quadrate, slightly papil- 

 lose ; branch-leaves much shorter and smaller, rounded and sub- 

 obtuse or shortly pointed, papillose, with short cells. Fruit 

 resembling that of the last species, but shorter, and with a shorter, 

 not rostrate beak. 



Hab. Mountain rocks in shady places; very rare; Highlands of Scotland. 

 Barren in Britain. 



Very closely resembling the last in habit, with the branching somewhat more 

 pinnate ; but the stem-leaves are quite different. Occasionally in H. heteropterum 

 they are longly acuminate and somewhat recurved ; but never with the abruptly 

 squarrose, filiform-acuminate points, nor with the elongated smooth areolation of the 

 present species. The branch-leaves in the two are, however, almost identical. 



99. PSEUDOLESKEA B. & S. 

 (Leskea nonnull. auct.J 



Plants with the habit and vegetative characters of Leskea, 

 and the fruiting characters of Heterocladium. Paraphyllia 

 numerous; nerve single ; capsule curved, inclined ; peristome 

 well developed, inner frequently with cilia. Dioicous. 



f Ls. usually denticulate at apex, nerved nearly to apex i . atrovirens 



\Ls. entire, nerve i or i length of leaf z, catenulata 



