Evans: Hepaticae of Puerto Rico 167 



broad and rounded at the apex, entire along the margin, and vari- 

 able at the base, being sometimes cuneate and sometimes rounded 

 or subcordate. The line of insertion is slightly arched and there 

 is sometimes a rudimentary radicelliferous disc at the base. Ex- 

 cept on the caudex, however, rhizoids are very scantily de- 

 veloped. 



In the majority of cases the inflorescence is dioicous, but a few 

 autoicous species have been described. The female inflorescence 

 is borne on a secondary stem or one of its leading branches and 

 usually innovates on only one side. In a few species, however, 

 two subfloral innovations are occasionally developed. An inno- 

 vation spreads obliquely and frequently forms a second arche- 

 gonium after bearing only one or two pairs of foliage leaves. 

 When this procedure is repeated several times in succession, a 

 cymose flower-cluster is the result, in which the flowers seem to 



be borne along the upper side of a floral axis. In rare cases an 

 innovation is terminated by an antheridial spike. The bracts are 

 unequally bifid and sharply complicate but are apparently never 

 winged along the keel. The lobes spread obliquely and are rela- 

 tively narrower than in the leaves, often showing a tendency to be 

 sharp-pointed at the apex. The lobule is also narrow and varies at 

 the apex from rounded to acute. The bracteole is free and ovate to 

 obovate in outline, the apex showing all variations in different species 

 from rounded or retuse to bidentate or bifid. In both bracts and 

 bracteoles the margins are commonly entire. The perianth is 

 oblong to obovate in outline, with a rounded or truncate apex and 

 a short beak. It is more or less compressed with sharp lateral 

 keels (figure 8). The antical surface commonly bears a short 

 and low keel in the upper part, while the postical surface bears 

 two sharp and confluent keels extending to below the middle. 

 Both lateral and postical keels usually develop narrow and inter- 

 rupted wings which are either irregularly sinuous or angular- 

 dentate along the margin. In other respects the surface of the 



perianth is smooth. 



The male inflorescence is large and conspicuous, terminating a 

 secondary stem or one of its leading branches ; in many cases, how- 

 ever, it proliferates at the apex. The diandrous bracts are loosely 

 imbricated and unequally bifid, both lobe and lobule being either 





