HANDBOOK OF BRITISH HEPATIC^;. 271 



male receptacles stalked, often with four 

 indistinct angles, marked on the top with a 

 cruciate crest ; frond obcordate, innovant 

 from the sinus. 



Marchantia commutata, Linden. Hep. Eur. 

 101. Marchantia hemisphcerica, Hook. Br. 

 Fl. V., 104. Marchantia androgyna, Eng. Bot. 

 t. 2545. Preissia commutata, Nees Hep. Eur. 

 p. 117 ; Cooke Hep. f. 188 ; Carr. and Pears. 

 Exs. 208, 209. 



Side of mountain streams. 



Fronds procumbent, imbricated, oblong, I to 3 

 inches, generally forked, rarely simple, waved and 

 crenate at the margin, dark green above, frequently 

 with a dark central line indi- 

 cating the midrib, underside often 

 purple at the margin, midrib promi- 

 nent, with numerous silky radicles, 

 beset on each side with purple scales. 

 Monoicous or dioicous. Male recep- 

 tacle with short pedicels springing from 

 the midrib in a sinus at the end of 

 the frond, receptacle peltate, flat and 

 papillose above, purplish, margins re- 

 flexed, cut into four or eight rounded 

 lobes. Female receptacle with pedicels 

 2 to 4 inches long, hemispherical, cut 

 at the margin into from four to ten or 

 eleven obtusedeflexedlobes,coveringas l ^' 

 many involucres, which have entire margins. Calyx 

 white, quadrifid, two to three in each involucre. 

 Capsule scarcely protruded when mature on a 



