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, adunca, 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 them in most 
* Spec. Hepat. 4: 1-30. 1909. 
