Evans: HEpaATICAE OF PUERTO Rico 559 
Gottsche,* which is known from Asia and from the Mascarene 
Islands. The only species which has been reported from Puerto 
Rico is the type of the genus, ZB. Jilicina, but it is probable that 
other species remain to be discovered. Unfortunately for the sys- 
tematist certain members of the genus are exceedingly variable, 
and it often becomes difficult, on this account, to discover valid 
differential characters between closely related species. 
The distinction between a prostrate caudex and secondary stems 
is even better marked in Bryopteris than in Mastigolejeunea. The 
caudex, which is sparingly and irregularly branched, is closely 
appressed to the substratum, clinging to it by means of numerous 
thizoids. The secondary stems spread widely from the substratum 
and develop few or no rhizoids. They are slender, but more or 
less elongated, sometimes attaining a length of 30 cm. or more. 
The stems exhibit a pinnate branching and the branches are usually 
Short and limited in growth. For these reasons and _ also be- 
cause the branches develop in one plane, the secondary shoot-sys- 
tems acquire a characteristic fern-like appearance, which accounts 
for the generic name. In some species the branches normally 
remain simple ; in others they tend to be more or less subdivided. 
The branches usually bear smaller leaves than the main axis, but 
strongly resemble it in other respects. In B. senuicaulis Tayl., how- 
‘ver, and probably in other species, slender flagelliform branches 
are often produced upon which the leaves and underleaves are not 
only minute but exhibit modifications in form and structure. 
An apparent exception to the pinnate form of branching is 
found in ZB. diffusa, which is described in the literature as dichoto- 
mous. Of course a true dichotomy is unknown among the /uzg- 
‘manniaceae, and an examination of this species shows that the 
branching is really monopodial in character, just as in the other 
Members of the genus. A branch, however, is as robust as the 
main axis and deflects it to one side, thus producing the effect of a 
fork. The branches are farther apart than in the other species 
and tend to be unlimited in growth and to become branched them- 
Selves in the same manner as the original axis. In this way the 
entire shoot-system seems to be made up of a series of dichotomies. 
_ From a morphological standpoint the branches in Bryopterss 
*Ann. Sci. Nat. Bot. IV. 8: pl. 16. f. 19-28. 1857. 
