98 HANDBOOK OF BRITISH MOSSES. 



t. xxv. ; (Moug. ty Nest. n. 625 ; a barren specimen mixed with 

 the next.) 



On stones in rivulets, by mill-clams, etc. From Yorkshire 

 to Sussex. Bearing fruit in spring. 



Of this, like the last, I have seen no fertile specimen. It is 

 clearly allied to H. serpens, especially to the stronger-nerved 

 form, but is distinguished by the larger size and opaque 

 areolation. From the next it differs in being far more rigid, 

 the pinnate branches, closer areolation, more 'slender nerve, 

 shorter sporangium, broader leaves, which are deltoid at the 

 base, and less acute lid. 



35. H. fluviatile, Swart z ; stem prostrate, ascending above 

 with more or less depressed branchlets ; leaves rather loosely 

 set, erecto-patent, concave, ovato-lanceolate, acute, entire, 

 with a very strong nerve ; fruitstalk even ; sporangium cy- 

 lindrical, curved ; lid conical, acute. Hook. Wils. t. Iv. ; 

 (Moug. Nest. n. 625, with a barren specimen of the last in 

 my copy.) 



On stones in rivulets. Scotland and Wales. Bearing fruit 

 in May and June. 



Monoicous ; forming large dark-green or reddish tufts. 

 Stem prostrate, slightly branched, naked below with a few 

 radicles; the branches and remote branchlets suberect, droop- 

 ing or prostrate ; leaves loosely imbricated, incurved when dry, 

 ovato-lanceolate, acute, concave, quite entire, with a very 

 strong reddish nerve, which reaches almost or quite to the tip, 

 and is often dilated above ; margin slightly recurved below ; 

 leaf-cells rather short; fruitstalk even, an inch long; sporan- 

 gium elongated, cylindrical, curved, especially when dry ; lid 

 conical, with a sharp point. 



36. H. riparium, L. ; stem prostrate, free above, irregularly 

 and remotely branched ; leaves loosely set, spreading, ovato- 



