PLAGIOTHEC1UM. 433 



usually 140-160 ix in the smallest forms, and 5-7 fi wide at the least, whereas in the 

 present species they are probably never more than J^iin width at the most, and 

 rarely so much, while the basal areolation and structure is quite distinct, the present 

 plant having the leaves rounded and narrowed at base to the insertion, and not 

 decurrent, with the cells almost uniform to the base, while in P. denticulatum they 

 are not rounded at the angles, but straight, decurrent, and with much laxer basal 

 cells. The inflorescence is also an important character. 



P. depressum is much like the present species in habit, but the leaves are 

 smaller, narrower, and not finely acuminate, with much shorter and wider cells. 

 P. striatellum differs in the inflated angular cells, autoicous inflorescence and striated 

 capsule. 



P. Borrerianum usually produces bundles of filamentous offshoots in the axils of 

 the leaves, bearing minute rudimentary leaves ; these are sometimes very abundant 

 and conspicuous, and may then I believe be relied upon as a distinctive character, 

 though they are not always present. 



3. Plagiothecium pulchellum B. & S. (Hypnum pulehellum 



Dicks. ; Isopterygium nitidum var. pulchellum Lindb.) 



(Tab. LV. F.). 



Very slender; forming small tufts of a bright green, with a 

 metallic sheen -when dry, often intermixed with other mosses. 

 Stems creeping, short, with numerous erect, curved, very slender 

 branches, £-inch long or less. Branch-leaves \ line long, usually 

 slightly falcate and regularly homomallous, hardly altered when 

 dry, very glossy, narrowly triangular, gradually narrowed 

 from, immediately above the wide, not excavate nor decurrent 

 base, to a very fine but not very long acumen, entire, plane at 

 margin, nerveless or with very faint traces of a nerve. Cells 

 linear, extremely narrow, 15-20 times as long as wide or more, 

 pointed, almost uniform ; about two rows at base short, wide, 

 sub-oval, but not distinct at angles nor forming auricles. Seta 

 slender, red, \-\ inch long, capsule small, very variable, usually 

 oblong with a tapering neck, suberect and slightly curved, with 

 a rather wide mouth ; sometimes very short, almost symmetrical, 

 or more strongly curved, and almost horizontal, frequently hardly 

 tapering at neck, especially before the fall of the lid ; greenish 

 brown, reddish brown when empty. Lid conical, apiculate. 

 Peristome teeth densely barred; cilia moderately developed. 

 Autoicous. 



Var. /3. nitidulum Husn. (Hypnum nitidulum Wahl. ; 

 Plag. nitidulum B. & S., Schp., Syn. ; Isopterygium nitidum 

 Lindb.). In flatter, more prostrate and straggling tufts, 

 branches spreading, not erect, complanate , leaves sub-distichous. 



Hab. Crevices of rocks and among mosses on mountains, frequent. The var. 

 more rare. Fr. summer. 



A very pretty species, sometimes forming rather dense tufts, at others growing 

 intermixed with other mosses, among which it interlaces itself and becomes 



CI 



