10 Evans: HeEpATICAE OF PUERTO RICO 
not formed the postical keel of the perianth is often distinctly two- 
angled. The lateral keels are sometimes very indistinctly winged, 
but they are never toothed. The male spike is short, and the 
bracteoles are limited to its base. Except for the perianth the 
genus has but little in common with Szictolejeunea. 
Two species of Neurolejeunca have been found in Puerto Rico, 
one by the writer and the other by Schwanecke and Sintenis. 
Neither appears to be abundant. Descriptions of these two 
species are given below and are followed by a description of 
Lejeunea portoricensis. | 
NEUROLEJEUNEA CATENULATA (Nees) Schiffn. 
Phragmicoma catenulata Nees, Naturg. Eur. Leberm. 3: 248. 
1838 (nomen nudum), 
Lejeunea catenulata Nees, in G. L. & N. Syn. Hep. 323. 1845. 
Symbwesidium catenulatum Trevis. Mem. R. Ist. Lomb. III. 4: 
403. 1877.5. 
Lejeunea (Neuro-Lejeunea) catenulata Spruce, Hep. Amaz. et And. 
84. 1884. 
Lejeunca (? Cerato-L ejeunea) catenulata Steph. Hedwigia 29: 131. 
1890. 
Neurolejeunea catenulata Schiffn. in Engler & Prantl, Nat. Pflan- 
zenfam. 1°: 131. 1895. 
Brownish-green, more or less glossy, growing in depressed 
mats : stems prostrate, 0.1 mm. in diameter, irregularly pinnate, 
the branches obliquely to widely spreading, simple or sparingly 
subdivided, usually with smaller leaves than the stem, sometimes 
distinctly microphyllous: leaves imbricated, the lobe plane or 
nearly so, falcate-ovate, measuring in the stem-leaves 0.9 mm. in 
length and 0.6 mm. in width, attached by an almost longitudinal 
line of insertion, antical margin arching partially or wholly across 
axis, outwardly curved to the broad and rounded apex, postical 
margin straight or slightly incurved, sometimes forming a con- 
tinuous line with the keel, sometimes slightly indented at the junc- 
tion ; lobule ovoid, 0.2 mm. long, 0.12 mm. wide, sometimes in- 
flated throughout, sometimes strongly inflated in the basal portion 
and plane in the outer half, keel slightly arched or almost straight, 
free margin curved, usually appressed to the lobe throughout its 
entire length but sometimes revolute at the base, sinus shallow 
unulate, apical tooth mostly two to four cells long and two cells 
wide at the base ; cells of lobe plane or nearly so, averaging g p at 
