222 H E P A . T I M. [Marchantia, 



whitish thickened margin ; the midrib scarcely distinguishable 

 on the upper surface but by a longitudinal depression ; beneath, 

 however, prominent and thickly covered, for its entire length, 

 with the usual fibrous radicles ; among these radicles, and al- 

 most concealed by them, arise, on each side of the midrib, a 

 few membranaceous, oblique scales, which are more evident upon 

 the young shoots or innovations, where the roots are fewer, 

 and are then of a purple colour ; occasionally scales of a similar 

 nature, but greenish colour, overlap the margin of the innova- 

 tions at the extremity. These scales, when seen in their more 

 perfect state, appear to be unequally two-lobed at their an- 

 terior margin. Fructification, as far as we have observed, con- 

 stantly dicecious. Male receptacle entirely sessile, arising, we 

 believe, always from the midrib in various parts of its surface ; 

 in its form and structure it resembles those of the two preced- 

 ing species. Female receptacle pedunculated; the peduncle dif- 

 fering from that of other Marchantice in being remarkably suc- 

 culent, as in Jungermannia epiphylla, becoming flat and ap- 

 parently membranaceous when dry, and having, as far as we 

 can observe, only one groove with one bundle of fibres ; this 

 peduncle is inserted in a concave disk, and is from two to four 

 inches long. The receptacle is conical, inclining to ovate, obtuse 

 at the summit, the margins are deflexed and cut into about six 

 very short emarginate lobes ; the involucres green, two-valved ; 

 calyx quadrifid, and each seeming to contain but one ovate cap- 

 sule., which is partially exserted and cut into several revolute 

 segments. The seeds are large, dark olivaceous, the spiral fila- 

 ments double. 



2. M. hemisphcerica ; receptacle of the capsules hemispherical cut 

 at the margin into from four to ten equal lobes, that of the 



anthers pedunculated. 



Marchantia hemisphserica. Linn. Sp, PL p. 1604. Schmid. Ic. t. 

 34. Engl. Bot. t. 503. and t. 2545. 9 (under M. androgyna, excluding 

 the two lower figures. J 



Marchantia androgyna. Linn. 9 



Marchantia quadrata. Scop. Cam. ed. 2. p. 63. 



Reboullia hemisphserica. Raddi in Opusc. Scient. di Bologna. DHL 

 Muse. t. 75. / 2. 



HAB. Sides of mountain streams and moist banks, not 

 uncommon, flowering in April. 



