Evans: Notes on genus Herberta 193 



lished in 1909,* seventy-one species are recognized. According 

 to the information at hand four species have since been described, 

 making seventy-five in all. This marked increase is due partly 

 to the more extensive material at the disposal of recent writers 

 and partly to their narrower interpretation of species. Of the 

 seventy-one species admitted by Stephani nearly all have a very 

 limited geographical range and no fewer than forty-seven are 

 described as new. Taking into account the species of his mono- 

 graph and those since published, two are restricted to Europe, 

 thirteen to Africa (including the Azores), sixteen to Asia (includ- 

 ing the Philippines), seven to various islands of the Pacific, ten to 

 tropical North America, and twenty-six to South America; Ste- 

 phani gives one species a wider range, including Samoa, Tahiti, 

 Hawaii, Japan, and Himalaya. It is interesting to note that he 

 accredits no species to North America north of Mexico, although 

 H. adiinca, a species which he restricts to Europe, has been re- 

 peatedly reported by American writers, not only from Alaska and 

 British Columbia but also from the eastern United States. 



The species of Herberta grow on rocks, on trees, and on the 

 ground and sometimes form extensive mats or tufts. In the tropics 

 they seem to be confined to higher altitudes, but the few species 

 which occur in temperate and frigid regions sometimes descend 

 to the level of the sea, this being true in both hemispheres. The 

 plants are usually marked by a yellowish or brownish color, due to 

 a pigmentation of the cell walls. In rare cases a reddish or 

 purplish tinge is present, and in sheltered stations the pigmentation 

 may be so slight that the plants appear green. 



Notes on the morphology of the genus 

 In its morphological features Herberta is one of the most clearly 

 defined and natural genera of the Hepaticae. The gametophyte 

 consists of a prostrate rhizome which gives rise to numerous secon- 

 dary stems. These sometimes remain simple, even when they 

 become comparatively long, and sometimes branch sparingly. 

 The subequally bifid leaves are slightly incubous while the under- 

 leaves are strictly transverse, and yet, since the underleaves are 

 nearly or quite as large as the leaves and similar to t hem in most 



* Spec. Hepat. 4: 1-30. 1909. 



