86 HEPATlCiE IN HIBBRNIA. 



the stem like the perich^tia, antheridia two or solitary, fixed in the 

 axils of semiglobosely concave bracts, rarely in the axils of leaves 

 or perichgetial bracts, the foot stalk commonly arcuato-curved, 

 paraphyses none. Propagula rather large, almost always disci- 

 form, arising from the leaves, 



b. Homogamae. 



Prothallium shortly filiform, entire or branched in the frondose 

 forms, bulbiform-snbglobose. Stem irregnlarly branched, with 

 branches from the amphigastrial axil, or with innovations more or 

 less approximate to the colesula, rarely dichotomons, pinnate or 

 twice compound. Leaves succubous or incubous, sometimes o]Dpo- 

 site and connate, very rarely conduplicate and then almost always 

 the front lobe is smaller, as to form highly variable, round or 

 reniform to sublinear, quite entire to broken up into filiform 

 segments. Amphigastria narrow, more or less ovato-lanceolate, 

 rarely round, quite entire to broken up into filiform segments, not 

 unfrequently none. Gamoecium dioicous, paroicous or much more 

 rarely autoicous. Pericha^tium passing out from the amphigastrial 

 axilla as a proper branch, either apical on the stem itself, and its 

 innovations, or in very many frondose forms, fixed on the interior 

 face, more or less below the apex of stem, sometimes saccato- 

 dependent. Pistillidia commonly very numerous. Colesula usually 

 large, three or five plicate, very rarely winged, sometimes compla- 

 nate or compressed, sometimes terete or densely plicate, with the 

 mouth more or less wide, hardly ever beak-shaped ; not un- 

 frequently none. Seta long or very long, often thickish. Tlieca 

 large globose-cylindric, of thick texture, brown and rfot pellucid, 

 as if formed • f at least two strata ; cut down to the base, with the 

 valves patent or divaricate, almost always showing spiral fibres 

 internally. Elaters two — rarely one — tri, or quadrispiral, adher- 

 ing to the internal face of theca, very rarely to apex of valves, or 

 free. Spores minute or rather large, sometimes appendiculate 

 externally. Androecia proceeding from the amphigastrial axilla 

 as perichietia, or antheridia, commonly two, more rarely more or 

 one, in the axils of the uppermost leaves, or in the frondose forms, 

 fixed over the anterior face of the stem or immersed in it ; the foot- 

 stalk straight, hardly ever arcuato-curved, paraphyses sometimes 

 present, usually filiform. Propagula minute, globose or angular, 

 formed of one or few cells, arising from the leaves, amphigastria 

 or apex of stem, very rarely large, more or less globose, and im- 

 mersed in the frond. 



t Opisthogamas. 



Stem irregularly branched by bifurcation of apex, or with 

 branches from the amphigastrial axillaj, sometimes pinnate or twice 

 compounded. Leaves incubous or succubous, very rarely condu- 

 plicate, entire or lobed. Amphigastria present at least in the 

 pericha^tium of all, very like the leaves, or more or less ovate, 

 undivided or lobed. Gamoecium dioicous, autoicous, rarely 



