I. — A Revision of the North American Species of Frullania, 

 A Genus of Hepatic.e. By Alexander W. Evans. 



With the single exception of Jungermannia itself, as defined by 

 most recent writers, the genus FruUania is the richest in species of 

 all our hepatic genera, and the plants belonging to it are so distinct 

 in their appearance and in their mode of life that the genus is one of 

 the earliest which students of the liverworts learn to recognize. All 

 of our species attain their best development in rather exposed locali- 

 ties, some of them on the trunks and branches of trees and bushes 

 others on rocks ; and, unless we see them soon after a shower or on 

 a moist, cool day, they appear quite shriveled up and lifeless. At 

 such times the plants are dark red or brownish-green in color, most 

 of them adhere closely to bark or rock, and their stems, toward 

 their extremities, look like fine, radiating, branched lines with round- 

 ish irregularities produced by the leaves ; in Fi'ullania squarrosa 

 the dry leaves are appressed to the stems and give them a some- 

 what worm-like appearance. As soon as the plants absorb water 

 they become strikingly different ; their stems and leaves are no 

 longer shrunken and brittle, but are turgid and flexible, and their 

 colors are more lively and distinct. Several of our species are not 

 absolutely restricted to exposed situations but are able to exist in 

 more sheltered jslaces; we find them, for example, on damp, shaded 

 rocks, on rotten logs, or creeping over or through tufts of mosses. 

 Such plants are rarely satisfactory for study, their leaves are more 

 scattered than is normal, they reproduce almost entirely by vegeta- 

 tive means, and they often fail to develop the water-sacs which are 

 80 characteristic of our genus. 



As in nearly all large and natural genera, the species of lYullania 

 are difficult to define. Many of them are widely distributed and 

 extremely variable, and the confusion to which these conditions 

 naturally give rise has been increased by the tendency among older 

 writers of magnifying slight or temporary differences between plants 

 into specific characters and, at the same time, of disregarding more 

 important points of distinction. In the Synopsis Hepaticarura of 

 Gottsche, Lindenberg and Nees von Esenbeck (published from 1844 

 to 1847), twelve species are accredited to us; four of these are 

 synonyms of the common F. Ehoracensis, leaving us, therefore, only 

 eight good species. Daring the forty years following the publication 

 Trans. Conn. Acad., Vol. X. May, 1897. 



