BRITISH HEPATICiE. 25 



corpuscles. Another form, fi* rigens, has also slender elongated shoots and small 

 leaves, and occurs in dense erect tufts from repeated prolifioation of the apex. 



Stolons mostly subterranean, less conspicuous than in allied 

 species, viticulose, fleshy. Stems (f. 8, 2) half an inch to an inch 

 in length, sometimes longer, simple or rarely furcate, the reju- 

 venescence of the plant being maintained by the growth of innova- 

 tions from the axils- of the apical amphigastria. The stems are 

 stout, sub-ligneous, in the var. a trigonous on section ; colour from 

 brown to dark purple. Barren shoots sub-terete, or laterally com- 

 pressed, of nearly equal diameter, curved at the summit, either 

 creeping, the apex only ascending, or erect, 



Rootlets numerous on the stolons and creeping stems, or dis- 

 posed in a fasciculate manner at the base of the amphigastria ; rarer 

 on the erect or fertile shoots, white, capillary. 



Leaves smaller and more distant at the base of the stems and 

 innovations, more crowded, and of nearly equal diameter upwards 

 (f. 8, 2, 3), distichous, scalately imbricated, erecto-patent or erect, 

 obliquely amplexicaul, concave, especially at the base, from \" to 

 Y in length, orbiculate (f. 8, 3), sometimes a little broader than 

 long, sub-marginate (the border a little inflexed and formed of 

 smaller cells), terminal leaves of fertile shoots emarginate. 



Amphigastria conspicuous on the upper portion of the shoots, 

 ovate, or triangular-subulate (f. 8, 5), patent or reflexed, frequently 

 connate with the margin of the adjacent left-hand leaf {spira dex- 

 trorsa), rarely with the leaves on each side ; subulate, deformed, or 

 obsolete at the lower part of the stem, or hidden by the capillary 

 rootlets ; margin entire, in some specimens reflexed. 



The texture of the leaves is rather thick and succulent, little 

 altered when dry. 



Colour deep green, olive, reddish-brown, or purple. 



Cells with continuous rather thick walls, but obscured by the 

 presence of numerous chlorophyll-granules, and large translucent 

 corpuscles of a round, oblong, or curved shape : these refract the 

 light like air-bubbles, and are very characteristic of the species 

 (f. 8, 4). The structure becomes clearer when the leaf has been 

 prepared by boiling with liq. potassse, and tinting with iodide of 

 zinc. The marginal cells are smaller, longer than broad, -^yw" by 

 T^oo" ; ^^ tbe upper third the cells are uniform, hexagonal, with 

 double contour, yys" to Tim" 5 Jiear the base of the leaf the form 

 is oval, -grg-g" by rlo"- Trigones minute, occupying the angles of 

 adjacent cells. 



Dioicous. Fertile stems ascending, stouter and incrassated at 

 the apex, trigonous on section, the flat surface being ventral. 

 Leaves in the var. major distant, plane, and often recurved at 

 the apex, the basal portion remaining ventricose. Involucral leaves 

 (f. 8, 6) two or three pairs, double the size of the ordinary leaves, 



E 



