Evans: HEpATICAE OF PuERTO RIco 219 
in the Taylor herbarium is exceedingly fragmentary but is sufficient 
to show that the species is distinct not only from Spruce’s LZ. den- 
ticulata but also from P. aeguitexta. It is characterized by its nar- 
rower and more gradually acute leaves, by its smaller underleaves 
which are relatively broader and less deeply bifid, by its narrower 
bracteole with entire or subentire margin, and by its perianth which 
has a very rudimentary beak and sharply laciniate wings. Its 
inflorescence is apparently dioicous. Judging from the type- 
specimen, P. dicristata Steph., * also collected by L’Herminier on 
Guadeloupe, is a synonym of ZL. decora, although this could hardly 
be determined from Taylor’s very incomplete description. 
Prionolejeunea aemula (Gottsche) 
Lejeunea aemula Gottsche; G. L. & N. Syn. Hep. 338. 1845. 
Lejeunea (Priono-Lejeunea) aemula Steph. Hedwigia, 29: 69. 
1890. 
Lejeunea (Prionolejeunea) vulcanica Spruce, Jour. Linn. Soc. 
Bot. 30: 337. pl. 27. f. 1-7. 1894. 
Prionolejeunea vulcanica Schiffn. Bot. Jahrb. 23: 590. 1897. 
Dull pale green, becoming brownish upon drying, loosely 
tufted and often mixed with other hepatics: stems 0.09 mm. in 
diameter, prostrate and loosely adherent to the substratum, spar- 
ingly branched, the branches obliquely to widely spreading : leaves 
slightly imbricated (or sometimes distant on small-leaved branches), 
the lobe obliquely spreading, convex, scarcely falcate, 0.5 mm. 
long, 0.45 mm. wide, outer part ovate to orbicular, very abruptly 
dilated from a narrow and contracted basal region, antical margin 
strongly incurved near the’ base then strongly outwardly curved 
to apex, postical margin also strongly outwardly curved, forming 
an angle of g0° or less with the keel, apex broad but usually 
abruptly apiculate or short-acuminate, whole margin (except close 
to the antical base) densely and regularly denticulate from pro- 
jecting cells; lobule inflated throughout, ovoid, 0.17 mm. long, 
0.12 mm. wide, keel strongly arched, free margin curved, involute 
to apex but usually appressed to lobe, sinus broad and lunulate, 
apical tooth slightly curved ; cells of lobe slightly convex, aver- 
aging 20 » at the margin, 24 4 in the middle and 35 x 24 pat the 
base, rather thin-walled, trigones and intermediate thickenings 
small but distinct: underleaves distant, orbicular, 0.2 mm. long, 
bifid about one half (to within two or three cells of the radicellif- 
€rous region) with erect triangular lobes, acute or obtuse or even 
* Hedwigia, 35: 118. 1896. 
