562 Evans: HEPATICAE OF PuERTO RICO 
to one sixth with obtuse lobes and sinus, margin as in lobule ; 
perianth obovoid or clavate, 1.1 mm. long, 0.6 mm. in diameter, 
slightly narrowed toward base and truncate above, beak obsolete, 
terete toward base, sharply five-keeled in upper part, the keels 
rounded above and narrowly, often obsoletely alate, whole surface 
of perianth roughened, due in the lower part almost entirely to 
convex cell-walls, in upper part to tubercles: ¢ inflorescence 
occupying a short branch or terminal on a leading branch ; bracts 
in two to ten pairs, strongly inflated, unequally bifid, the lobe 
mostly rounded, the lobule subacute; bracteoles similar to the 
underleaves but smaller, found only at the base of the spike ; an- 
theridia in pairs: ripe sporophyte not seen ( f/. 22, f. 77-22). 
On bark of trees. North slope of the Luquillo Mountains, 
Heller (4745). El Yunque, Evans (189 f.p.). Originally collected 
by Spruce, in Brazil, and distributed in Hepaticae Spruceanae. 
The presence of a subfloral innovation in 7: Aquarius was orig- 
inally looked upon as a somewhat aberrant character. Within 
recent years, however, several other species have been referred to 
Trachylejeunea, in which an innovation of this nature is of occa- 
sional or even of constant occurrence. There is little danger of 
confusing any of the other Puerto Rico Lejeuneae with this very 
distinct species. Its robust size and pale color, together with its 
avidity in absorbing water, recall perhaps certain species of 7ygve- 
lejeunea or Taxilejeunea, but its strongly tuberculate leaves and 
perianth and its large lobules with their peculiar apices, will at 
once separate it from both these genera. From the genera Harpa- 
lejeunea and Strepsilejeunea, to which it is really more closely 
allied, it may be distinguished by its large size and blunter leaves, 
as well as by other less apparent differences. 
Even among the other Zrachylejeuneae of tropical America, 
T. Aquarius has no very near relatives. The South American 
Lejeunea (Trachy-Lej.) pellucidissima Spruce * and ZL. (7) vachy-L¢-) 
pandurantha Spruce * resemble it somewhat in size, color and 
general appearance, but both of these species are destitute of true 
subfloral innovations, and their leaf-cells, although more or less 
convex, are without tubercles and are either thin-walled through- 
out or have walls which are slightly and uniformly thickened. 
YALE UNIVERSITY. 
* Hep. Amaz. et And. 184. 1884. 
