86 NEW BRITISH HEPATIC.E. 



so as to resemble scales. In this state it may be confounded with 

 R. nigrella, D.C., a species first discovered by Mr. Ralfs, at Bar- 

 mouth, and published under the name of R. lamellosa. The two 

 species grow near each other, R. nigrella on damp banks, and R. 

 bifurca on limestone cliffs. The former is smaller in all its parts, 

 with linear dichotomous lobes (pi. 18, f. 9), margin membranou , 

 entire, expanded, and dark-green when moist, but when dry re- 

 markably inflexed, and displaying the dark-purple scales which 

 clothe the inferior surface, and which are rounded and closely im- 

 bricated. In this state the fronds have a peculiar wiry look, quite 

 different from their aspect after rain. In R. lamellosa, Raddi, the 

 under side is concolorous, and the scales are pale and scariose, 

 much narrower, and projecting beyond the margin. 



In R. glauca the fronds are of uniform colour on both surfaces, 

 texture much thinner, margins plane, acute, or slightly inflexed. 

 From "Ross Bay in Ireland, and Penzance, I have received a small 

 var., in which the margin is purple, but not thickened as in R. bifurca. 



When I first collected this species at Barmouth, I thought it 

 probably a form of R. glauca, the fleshy habit of which might 

 depend on the sea air, as in Cochlearia, Silene, &c. Recently, how- 

 ever, I have received authentic specimens from Prof. Lindberg, a 

 drawing of which I give at fig. 4, and which differ in no respect 

 from our own plant, except that the lobes are more oblong. 



PI. 18, fig. 1. R. bifurca, natural size. 2, 3, 4, 5 fronds X 16 



diam. 6, transverse section. 7, the same X 60 diam., showing the 



cellular structure. 8, spores X 250 diam. 9, R. nigrella, D'Cand. 



Upper surface when dry and inflexed, showing the lamellate scales. 



Riccia sorocarpa. Bischoff. 



Segments of the frond linear, sub-dichotomous, carinate-sulcate, 

 green on both surfaces ; lobes thick and fleshy, oblong, obtuse, or 

 emarginate ; margin thin, glabrous, inflexed when dry ; fruit 

 scattered along the mid-vein. 



R, sorocarpa, Bisch. de Hep., in Nov. Act. A. Nat. Cur., xvii., 

 2. p., 1053, t. 71, f. 11. iexd. syn., R. minima?, Ruddi.) Syn. Hepat., 

 p. 600. Gott. and Raben. Hep. Eur. ex. n. 23. 543. 



R. minima, Leers Fl. Herborn, p. 252 {not Lindenberg Monog. 

 der Riccieen, p. 67, t. xx., f. 2). 



Hab. Great Doward Hill, near Ross, Hereford ; discovered by 

 Mr. H. 31. Watkins, growing on limestone rocks, 1862 ! 



Fronds forming shallow strata, divaricate-furcate, crowded 

 and entangled so as to be separated with difficulty ; colour pale 

 glaucous-green on both surfaces. 



Segments one to three lines in length, by \ to ^ of a line 

 broad, linear, the lobes patent or divergent. Upper surface cana- 

 liculate-sulcate, mid-vein distinct, margins expanded when moist 

 (f. 11, 15), except near the apex, where they are thin, membranous, 

 and erect or incurved (f. 13, 14). When dry the involution of the 

 margin is more decided, so as to hide the upper surface, and impart 

 to the frond a peculiar aspect (f. 16). Ventral surface nearly 



