30 BRITISH HEPATICiE. 



Hab. Not unfrequent by tlie borders of mountain rills, or spots moistened by the 

 spray of -waterfalls. Discovered by Miss Uutchins at Bantry Bay. Lough. Bray, 

 Br. Taylor I Baysdale, and Howden GUI, Cleveland, 1862, IF. Mudd I Near Tod- 

 morden, fr. AprU. 1860, J. Nowell ! Dartmoor, E. M. Holmes! Moors west of 

 Ingleburgh ! Succoth Hill, Arroquhar, A. McEinlay I Ben Sligott, Boss, C. Hovm I 

 Ben Mac Dhui, ^ and ^ , G. K Hunt I Ffynnon Faer, (J, and Llyn Ogwin, 5 , 

 North "Wales, W. Wilson ! Snowdon ! Fruit, spring. 



This fine species is semi-aquatic, occurring only in spots moistened by the drip 

 from rocks or waterfalls, or fringing the borders of mountain rills, or growing inter- 

 mixed with other species in Sphagnum beds. Conspicuous from the compressed habit 

 and the pellucid foliage, tinged with purple ffr claret. 



Stems (fig. 9, 1) ascending or erect, filiform, flexuose, from 

 1^" to 3" in length, in luxuriant specimens sometimes twice as 

 long, of a pale brown colour, simple or proliferous, from the ventral 

 aspect. 



Stolons long, branched, entangled, resembling the stems in tex- 

 ture, naked, or sparingly radiculose. 



Rootlets confined to the subterranean portions of the stems, and 

 stolons, rarely found on the terminal shoots, white, capillary. 



Innovations numerous, arising from the axils of amphigastria, 

 or rarely from the involucral bracts. Normally a single branch is 

 produced from the ventral apex of old shoots, which follows the 

 direction of the main axis, and without care may be thought 

 continuous with it ; and which becomes the fertile shoot of the 

 following year. 



Leaves -^" to -^" in diameter, smaller and more distant near 

 the base, terminal ones (except on barren stems) more crowded and 

 larger, " imbricating each other in a very regular and beautiful 

 manner" (fig. 9, 2), erect, appressed to the stem, plane or slightly 

 concave, so that the inner surfaces of opposite leaves meet. 



Form (fig. 9, 2, 3) orbiculate to reniform, sub-marginate, entire ; 

 dorsal margin decurrent for a short distance, insertion either at 

 right angles with the stem or more oblique ; ventral margin rounded 

 at the base. 



Texture thin and membranous, especially in submerged speci- 

 mens, shrinking and incurved when dry, sometimes more compact 

 and firm ; remarkably pellucid, "so as to sufier the stem to be 

 seen through them, dividing each of them, as it were, into two 

 nearly equal halves." * Colour of the inferior leaves pale green, or 

 yellowish-brown, upper ones of a purple or maroon colour. 



Cells (fig. 9, 5) with thickened walls, the marginal row. uniform 

 in size, sub-quadrate, -grs" in diameter. Those of the upper third 

 polygonal, ywo" to 5-5-3" by g^r"- Near the base of the leaf larger 

 and more oblong, 5^" to 3^" by yg^". Trigones indistinct. 



* Br. Jung. t. Iviii 



