402 HEPATICJE. 



rootlets few, delicate. Leaves closely imbricate, distichous, erect, 

 broadly ovate, ovate or oval, entire, irregularly lacerate-bifid, 

 erose or bidentate ; texture delicate, margin extremely so, mem- 

 branaceous, diaphanous, quite entire; the walls of the mar- 

 ginal cells hardly visible, except in young leaves, inner cells 

 smallish to small, roundish-quadrate, larger near the middle, 

 walls thick, angles thickened. No stipules. Bracts similar to 

 the upper leaves, innermost bracts small, very delicate. 

 Androecia terminal, perigonial bracts broadly ovate, swollen, 

 bidentate, with a small basal acute segment.. 



Dimensions. — Stems J to |^ inch long, with leaves '5 mm. 

 wide, '275 mm. x '2 mm. diam. ; leaves '7 mm. x '6 mm., 

 •9 mm. X "7 mm., -75 mm. x "G mm., '6 mm. x -55 mm., 

 •7 mm. X '5 mm ; segments "1 mm. ; cells "OS mm. x "02 ram., 

 •02 mm., -0175 mm. 



Hab. — Only found sparingly on high mountains. Extremely 

 rare. 15. Loch-na-gar, A. Croall, 1856. Ben Lawers, 

 W. Young, 1896 ; S. M. Macvkar, 1900. 16. Ben Nevis, 

 Br. Greville, 1830. 17a. Sutherland Mountains, Dr. Greville, 

 1830. 



I. Brandon Mountain, Dr. D. Moore, 1840. 



Found on the Continent and in North America, Alaska, 

 Krause. 



Obs. — Hardly to be recognised as an hepatic : the closely 

 appressed leaves give the stem the appearance of a lichen or coral, 

 but when examined under the microscope its character is at once 

 made out. 



Mounted in water or glycerine, and examined by transmitted 

 licvht, the leaves are so transparent that the stem can be seen 

 through them ; the extremely delicate hyaline margin, which is 

 quite smooth, and the usually entire or irregularly notched apex 

 distinguish it from Cesia concinnata or Cesia ohlu^a. 



In recent specimens collected by Mr. Mac vicar on Ben 

 Lawers, the young leaves are not weathered, and show the apex 

 to be distinctly but shallowly bidentate, sinus obtuse, segments 

 obtusate or slightly acute. 



