286 HANDBOOK OF BRITISH HEPATIC*:. 



berant on the surface, at length naked, by the 

 splitting of the middle groove; substance 

 geminate. Corda in Opiz. Nat. (1829). 



Rieeioearpus natans, C. 



Frond simple, or with innovations, about 

 -J inch long, pale green above, slightly 

 grooved in the centre, inversely heart-shaped, 

 purple beneath and clothed, especially at the 

 edge, with numerous long pendent fringe-like 

 flattened serrated hairs. 



Riccia natans, Linn. Syst. 956 ; Hook. 

 Muse. Brit. 214; Bot. Misc., p. 41, t. 22; 

 Eng..Fl. V., L, p. 99; Cooke Hep. f. 199; 

 Linden. Mon. 475, t. xxxi., xxxii. Rieeio- 

 earpus natans, Corda Sturm. XXII., XXIII., 

 p. 103, t. 32 ; Carr. and Pears. Exs. No. 141. 

 Lichen parvus vernus, &c., Dill. Muse. 536, 

 t. 78, f. 1 8 ; Ray's Syn. p. 116. 



Floating on water. (Fr. Summer.) 



The fronds float like duckweed, and are from 

 i to \ inch long, pale green above, 

 often tinged with purple towards 

 the margin and beneath, slightly 

 grooved along the centre of each 

 lobe, rough with minute scales on 

 the upper surface, and copiously 

 fringed at the margin, and clothed 

 beneath with long pendent flat 

 197. membranaceous hairs (fig. 197). 



