274 Evans: HEPATICAE OF PUERTO RICO 
sinus lunulate, about three cells long, hyaline papilla in the sinus 
but displaced one cell from the margin, keel arched near base, 
roughened from conical cells; cells of lobe averaging about 18 X 
14u in the middle, plane to strongly convex or conical, usuall 
thin-walled throughout: inflorescence paroicous: 9 inflorescence 
borne on a simple stem (in all observed instances), innovating on 
one or both sides, the innovations simple and sterile; bracts 
obliquely spreading, sometimes scarcely complicate, subequally 
bifid, the lobe ovate, 0.15 mm. long, 0.06 mm. wide, apex and 
margin as in the leaves, lobule ovate-lanceolate, 0.15 mm. long, 
0.05 mm. wide, acute and usually bearing a second sharp tooth 
on the inner margin near the apex, otherwise entire; perianth 
obovoid, 0.3 mm. long, 0.25 mm. wide, terete in upper portion, 
rounded above and bearing a short and broad, sometimes obsolete, 
beak, surface smooth below, rough in upper half from conical 
cells: o& bracts in a single pair below the involucre, monandrous, 
otherwise like the normal leaves: capsule about 0.1 mm. in diam- 
eter; spores Qu in short diameter; elaters 5u wide. (PLATE 12, 
FIGURES 4-10. 
On living leaves. El Yunque, Evans (21, in part, mixed with 
Cyclolejeunea accedens and Drepanolejeunea infundibulata). 
The present species shows the contrast between normal and 
rudimentary leaves in a very marked way. In a normal leaf the 
lobule is relatively large and the lobe projects beyond the water 
sac for only about one fourth itslength. The projecting portion 
is rarely more than three or four cells long and four or five cells 
broad; it is usually distinctly concave, the margin on each side 
being curved upward. All the cells in the projecting portion are 
strongly convex, thus giving the effect of marginal crenulations; 
in the vicinity of the keel the cells tend to become conical and 
occasionally show a slight thickening of the wall at the apex of 
the cone. The free margin of the lobule is appressed to the lobe 
as far as the apical tooth, which projects slightly beyond the 
proximal tooth at its base. The rudimentary leaves (not shown 
on the plate) are scattered about among the normal leaves, and 
many of the plants fail to show them altogether. The lobes in 
such leaves are narrow and lanceolate, perhaps four or five cells 
long and three or four cells broad, and the lobules are often repre- 
sented by a single cell. Aside from the subfloral innovations 
branching seems to be exceedingly rare, and there seems to be no 
