26 Evans: HeEpATICAE OF PUERTO RICO 
branches obliquely or widely spreading : leaves more or less im- 
bricated, the lobe erect and subparallel with the axis or slightly 
spreading at the base with the apex turned forward, strongly con- 
vex, oblong-ovate to ovate-lanceolate, 0.3 mm. long, 0.17 mm. 
wide, somewhat narrowed toward the base and attached by a short 
slightly oblique line of insertion, margin subentire or indistinctly 
crenulate or denticulate from projecting cells, antical margin 
arched, postical margin more or less involute beyond keel, in ex- 
planate leaves forming a continuous line with keel, apex varying 
from rounded to acute, on slender leaves occasionally tipped with 
two superimposed cells; lobule strongly inflated throughout, 
ovate, 0.17 mm. long, 0.09 mm, wide, keel strongly arched, 
slightly roughened in outer part from projecting cells, free margin 
involute to beyond apex, then passing by a lunulate sinus to end 
of keel, apical tooth slightly curved (not clearly visible without 
dissection) ; cells of lobe convex, averaging 19 # in diameter, with 
large and conspicuous trigones and occasional intermediate thick- 
enings separated by small pits, convex wall also thickened, cell- — 
cavities varying from rounded to distinctly stellate, base of lobe 
showing an indistinct group of elongated cells as in D. subulata ; 
ocelli none ; cells of lobule thickened but without distinct trigones : 
underleaves distant, basal portion trapezoidal, 0.05 mm. long, 0.04 
mm. wide at the base, marginal cells six, the middle one on each 
side more or less bulging but less distinctly so than in Leffole- 
Jeunea exocellata, divisions widely spreading, each consisting of two 
or three cells in a single row, with a spread of 0.07 mm. : cells of 
underleaf with distinctly thickened walls: inflorescence dioicous : 
? inflorescence on a short branch, innovating on one side with a 
simple and sterile innovation ; bracts obliquely spreading, compli- 
cate, shortly and unequally bifid, the lobe ovate, falcate, 0.5 mm. 
long, 0.35 mm. wide, obtuse to acute, entire or irregularly repand 
and denticulate, lobule oblong, 0.25 mm. long, 0.08 mm. wide, 
truncate, scarcely separated from lobe; bracteole free or nearly 
so, oblong-obovate, 0.35 mm. long, 0.25 mm. wide, bifid about 
one third with a broad sinus and triangular acute divisions : 
perianth and ¢ inflorescence unknown (f/. 2, f. 1-13). 
Onalog. El Yunque, Evans (89 £.f). 
The nearest ally of this new species is apparently D. subudata. 
The two plants resemble each other in their convex leaf-lobes 
which are erect or approximately so, in the group of elongated 
cells at the base of the lobe, and in the slightly curved terminal 
tooth of the lobule. JD. crasstretis differs from D. sudu/ata in its — 
_blunter leaves, in its smaller leaf-cells which have thickened 4 
