Evans: HEpATICAE OF PuEerto Rico 561 
Trachylejeunea Aquarius (Spruce) 
Lejeunea (Trachy-L cjeunea) Aquarius Spruce, Hep. Amaz. et 
And. 185. 1884. 
Pale whitish green sometimes tinged with yellowish, growing 
in depressed mats or mixed with other bryophytes: stems 0.1— 
0.15 mm. in diameter, sparingly branched, the branches widely 
spreading : leaves imbricated, the lobe widely spreading, strongly 
convex and reflexed at the apex, falcate-ovate, sometimes broadly 
so, 0.6 mm. long, 0.45 mm. wide, attached by an almost longi- 
tudinal line of insertion except for a short distance near antical 
base, margin entire near antical base and also near keel, otherwise 
crenulate from projecting cells, sometimes obscurely serrulate or 
denticulate near apex, antical margin straight or slightly incurved 
near base, then strongly outwardly curved and arching to the 
middle of the axis or beyond, postical margin slightly curved, 
apex obtuse to subacute, on leaves of slender branches sometimes 
acute ; lobule ovoid, 0.2 mm. long, 0.1 mm. wide, strongly in- 
flated, keel strongly arched, roughened in outer part from project- 
ing cells and warts, free margin strongly involute to beyond apical 
tooth, then passing by a very shallow sinus to end of keel, apical 
tooth slightly curved, hyaline papilla at proximal base of tooth in 
a depression bounded on the inner side by a second more or less 
distinct unicellular tooth; cells of lobe with strongly convex outer 
walls, averaging 18 » at the margin and 24 in the middle, each 
cell (except near the base) bearing a median, blunt tubercle repre- 
senting a local thickening of the convex wall, trigones large and 
conspicuous, rarely confluent, intermediate thickenings wanting ; 
ocelli two to five in number, measuring 65 x 28 , situated in a 
group near the base of the lobe; tubercles occasionally present 
on margin between adjoining cells; cells of lobule also tubercu- 
late: underleaves distant, broadly orbicular-rhombic, 0.25 mm. 
long, 0.3 mm. wide, bifid to about the middle with connivent 
or suberect lobes and narrow acute sinus, not cordate at base, 
margin entire; rhizoids growing in tufts from the bases of 
the underleaves : inflorescence autoicous: 9 inflorescence borne 
on a short branch, innovating on one side with a short sterile in- 
novation ; bracts obliquely spreading, more or less complicate, 
unequally bifid, the lobe obovate, 0.75 mm. long, haces & Fouad wide, 
apex rounded to very obtuse, margin and cells as in leaves, lobule 
lanceolate, 0.4 mm. long, 0.15 mm. wide, apex obtuse to sub- 
acute, margin slightly and irregularly crenulate or verruculose in 
upper part, cells otherwise smooth or nearly so ; bracteole free, 
oblong to obovate, 0.6 mm. long, 0.3 mm, wide, bifid one eighth 
