Evans: HeEpatricaE OF PurerRto RIco 215 
In the following pages five species of Prionolejeunea from Puerto 
Rico are described. One of these is P. aemula (Gottsche), already 
known from two of the Lesser Antilles ; the others are apparently 
new. Itis probable that further exploration of the island would 
increase the list of species very materially, since several sterile and 
indeterminable forms occur in the collections already made. It is 
also probable that the geographical distribution of one or more of 
the new species will eventually be found to extend into the neigh- 
boring islands. 
Prionolejeunea innovota sp. nov. 
Dull yellowish green, becoming brownish upon drying, loosely 
and intricately caespitose: stems 0.09 mm. in diameter, prostrate 
and loosely adherent to the substratum, sparingly branched, the 
branches obliquely to widely spreading: leaves contiguous or 
subimbricated, the lobe widely spreading, more or less convex, 
falcate, 0.35 mm. long, c.3 mm. wide, outer part ovate-orbicular, 
abruptly dilated from a narrow basal region, antical margin 
straight or slightly incurved near base then strongly outwardly 
curved to apex, postical margin also strongly curved, apex broad, 
apiculate or abruptly acute, whole margin (except close to the 
antical base) sharply denticulate from projecting cells, the teeth 
regular except in the apical region ; lobule ovoid, 0.15 mm. long, 
0.1 mm. wide, inflated throughout, keel arched, forming a distinct 
angle of 90° or more with postical margin of lobe, free margin 
involute to beyond apex, sinus short and lunulate, apical tooth 
rather sharp and distinctly curved; cells of lobe slightly convex, 
averaging 14 x 16 wat the margin, 28 » in the middle and 35 x 234 
at the base, walls rather thin, the trigones and the occasional 
intermediate thickenings small and sometimes indistinct’; under- 
leaves distant, orbicular, 0.15 mm. long, bifid one half to two 
thirds (to within two or three cells of the radicelliferous portion) 
with erect, triangular and acute lobes separated by a broad, acute 
to lunulate sinus, margin usually with one or two short angular 
teeth on each side, otherwise entire : inflorescence autoicous : Q 
inflorescence on a very short branch, innovating on one side, the 
innovation sometimes short and sterile, sometimes an antheridial 
spike; Q bracts widely spreading, the lobe obovate, 0.5 mm. 
long, 0.3 mm. wide, rounded, apiculate or acute at the apex, mar- 
gin almost as in the leaves but the teeth sometimes a little more 
irregular, lobule oblong to lanceolate, 0.2 mm. long, 0.12 mm. 
Wide, blunt or acute at the apex, margin entire or slightly dentic- 
ulate ; bracteole free, broadly ovate or orbicular-ovate, 0.35 mm. 
long, 0.3 mm. wide, bifid about one half with acute, erect or con- 
