2 A. W. Evans — N'orth American Species of Frullania. 



of this work, new North American species were described from time 

 to time, mainly by Austin, until, in 1884, Professor Underwood' 

 was able to ascribe to our region twenty species of the genus. Of 

 these twenty species, however, three are synonyms and two of the 

 others, F. Peyinsylvanica and F. Hutchmsice, var. (in reality the 

 same plant °), have been transferred to the closely allied genus 

 Juhula. This leaves sixteen species known at that time, including 

 F. injiata, which is omitted in Professor Underwood's paper. The 

 few new species which have been added since 1884 and the few 

 described in the present paper, increase the number to twenty-two, 

 of which several are still known to us only from scanty or incomplete 

 material. 



The generic characters of F-ullania are so well stated in accessible 

 literature, particularly in the writings of Spruce' and of Schiffner% 

 that it would be superfluous to detail them here. The remarks 

 which follow are simply to call attention to certain interesting 

 peculiarities in leaf and perianth and to make clearer the specific 

 descriptions given later on. 



The leaves of Frullania are unequally complicate-bilobed, and the 

 antical or "dorsal" lobe, which is called simply the "lobe," is larger 

 than the other, spreads obliquely from the stem and is more or less 

 orbicular in shape. In most cases, one side of this lobe arches over 

 the stem and is often produced at the base into a cordate or auriculate 

 expansion ; the other side passes by a short and abrupt fold (except 

 in F. arietlna) into the postical or " ventral " lobe of the leaf. This 

 lobe, in turn, is deeply divided, usually to the very base, into two 

 unequal segments. The outer segment or " lobule " is the so-called 

 " auricle " of older writers ; it is an extremely variable organ, but, 

 in all of our species, is normally hooded over and inflated, sometimes 

 throughout its whole extent, into a galeate or clavate structure, 

 which serves as a sac or reservoir for the temporary retention of 

 water.^ The inner segment or "stylus" is usually much smaller 

 than the lobule and is reduced in some cases to a minute, subulate 

 process consisting of only three or four cells ; in T. Asagrayana^ 

 however, and in a few species allied to it, the stylus is larger and 

 forms a disc-like cellular plate of considerable size. In F. Caroli- 



1 Bull. Illinois State Lab. Nat. Hist., ii: 61-68. 1884. 



2 Cf. Underwood, Bull. Torrey Bot. Club, xix: 301. 1892. 



3 Hep. Amaz. et And., 3. 1884. 



4 Bngler and Prantl, Die naturlichen Pflanzenfamilien, Lief. 112: 132. 1895. 

 * Goebel, Ann. du Jard. Bot. de Buitenzorg, vii: 21. 1888. 



