410 A. W. Evans — Hawaiian Hepaticm of the Tribe Juhuloideoe. 



An objection to this procedure may be found in the fact that other 

 writers, notably Stephani, have used these names as generic, previous 

 to 1893; but as these writers did not define their genera, it would 

 complicate matters and be inconsistent with customary usage to 

 quote them as authority for their new combinations, excepting of 

 course those published since 1893, 



Of the forty genera recognized by Schiffner, Stephani* accredits 

 seventeen to the Hawaiian Islands, and the addition of Microlejeunea 

 as a distinct genus makes eighteen. Two species, L. ungulata and 

 X. calyptrata of Angstrom, he leaves doubtful; the first of these is 

 the same as Mitten's L. uncinata and is therefore a Drepanolejeunea., 

 but the second belongs in the distinct genus Colurolejeunea. The 

 writer is able to add the genus Trachylejeunea to the list, making 

 twenty genera in all. It is evident, however, that this number is not 

 quite correct: several of the genera are apparently listed on incorrect 

 determinations and certain species appear to the writer to fit some- 

 what more naturally into other genera than those to which they have 

 been assigned. By making these exclusions and transferences, four- 

 teen genera are left. As many of these are represented by a single 

 species each, it has seemed most practicable in the following key to 

 lead directly to the species represented on the Islands, rather than 

 to have short special keys under the respective genera. 



ICey to the species of Haioaiian LejeuneecB. 



Underleaves present, normal in number (i. e. one for each pair of 

 side-leaves). 



Underleaves undivided. 

 Leaves entire. 



? inflorescence borne on a principal branch, without 



innovations. Lopholejennea subm(da. 



$ inflorescence borne on a very short branch, with a 

 short, sterile innovation. [Platylejeiinea.) 



Underleaves broadly reniform. 



Platylejeiinea baccifera. 

 Underleaves orbicular. 



Platylejeiinea cryptocarpa. 

 $ inflorescence borne on a principal branch, innovating 

 on one or (very rarely) on both sides. 



lirachiolejeunea Sandv icensis. 

 Leaves usually more or less toothed at apex. 



X Cf . Biill. de I'Herb. Boissier, v, 843. 1897. Dicranolejeunea is omitted from 

 this list. 



