220 H E P A T I C M. [Marchantia. 



side constitutes a prominent blackish midrib, whence, for 

 nearly the whole length of the plant, spring numerous pale, 

 silky, fibrous radicles. The colour is generally a uniform dull 

 , green ; the texture between fleshy aud membranaceous, more 

 approaching to the latter, strikingly cellular, the cells 

 oblong, furnished in the centre with a small pore, arranged 

 in parallel lines, diverging upward from the midrib at an 

 acute angle. Fructification dioecious ; fronds bearing anthers 

 similar to those bearing capsules. Male receptacle greenish, 

 the papillae purple, supported on peduncles springing from the 

 base of a sinus at the extremity of the frond, just beneath the 

 margin ; about one inch in length, obtusely quadrangular, 

 thickened upwards. On one side of the peduncle are two grooves, 

 each containing a bundle of filaments that pass through their 

 whole length and diverge on the under side of the peltate re- 

 ceptacle into as many rays as there are lobes to the receptacle. 

 Receptacle flat on the summit, horizontal, papillose, fleshy, thin 

 and membranaceous at the margin, and cut into about eight 

 short, rounded lobes. Anthers equal in number to the papillce 

 on the surface of the receptacle, and imbedded in its fleshy 

 portion. A vertical section shows them to be of nearly oval 

 form and reticulated structure, filled with soft granular matter ; 

 these anthers are surrounded by an ovate reticulated membrane, 

 attenuated above and opening by an orifice through the papillae 

 externally. On the underside of the receptacle are numerous 

 imbricated scales, radiating, so that each ray corresponds with 

 a marginal lobe of the receptacle, and there covers the diverg- 

 ing fibres above mentioned. Female fructification ; receptacle 

 of the capsules pedunculated ; the peduncle from one to three 

 or four inches long, arising as in the male fructification, and 

 similar to it in shape and structure, but not thickened above. 

 The receptacle is hemispherical, deeply divided to the base into 

 from eight to ten linear, cylindrical, deeurved rays, covering as 

 many involucres which are united at the base, and there in- 

 termixed with minute chaffy scales ; these involucres are oblong, 

 membranaceous, open at the extremity, and remarkably laci- 

 niated, enclosing at the base while young, two or three pendent 

 pistils, as in Jungermannia, each surrounded by an ovate quadri- 



