EvANS: TAXILEJEUNEA PTEROGONIA 109 
Lejeunea (Taxi-Lejeunea) pterogonia Spruce, Trans. Bot. Soc. 
Edinburgh 15:216. 1884. 
Taxilejeunea pterogonia Schiffn. in Engler & Prantl, Nat. Pflan- 
zenfam. 1°: 125. 1895. 
Pale green, often becoming yellowish or brownish with age, 
growing in loose mats and often mixed with other bryophytes: 
stems mostly 0.15-0.2 mm. in diameter, irregularly and usually 
sparingly branched, the branches obliquely to widely spreading, 
sometimes long and similar to the stem but often short, invariably 
so if sexual: leaves loosely imbricated, the lobe obliquely spreading, 
plane to strongly convex, scarcely falcate, ovate, mostly 0.8—1 
mm. long and 0.55—0.75 mm. wide when well developed, dorsal 
margin arching across the stem and conspicuously auriculate at 
the base, slightly curved in the outer part, ventral margin slightly 
curved and forming a wide angle with the keel, apex acute or 
apiculate and often tipped with a row of two cells, margin slightly 
and minutely crenulate from projecting cells, sometimes with 
one or two larger and sharper teeth in the vicinity of the apex; 
lobule when well developed inflated throughout, ovoid, about 
0.15 mm. long and 0.1 mm. wide, keel straight to slightly arched, 
free margin involute to beyond the apex, sinus very short, shallowly 
lunulate (in spread out lobules), apical tooth an almost straight, 
scarcely projecting rounded cell; lobule often imperfectly developed 
but usually evident; cells of lobe about 16 w in width along the 
margin, 32 x 24 uw in the middle, and 40x 24 » at the base, thin- 
walled but with distinct (and sometimes confluent) trigones and 
intermediate thickenings, the latter sometimes two in number in a 
long lateral wall, cuticle covered over with exceedingly minute, dot- 
like verruculae: underleaves loosely imbricated, convex (from be- 
low), the lateral margins often more or less involute, orbicular, 
mostly 0.6—0.9 mm. long, bifid one fourth to one third with anarrow, 
usually sharp sinus and broad, subacute, often contiguous or over- 
lapping divisions, distinctly auriculate at the base, the auricles 
usually contiguous or overlapping, margin minutely crenulate 
throughout as in the leaf-lobes: inflorescence autoicous: 9 inflores- 
cence usually borne on a very short branch but sometimes on a 
somewhat elongated branch, innovating on one side, the first inno- 
vation usually at once floriferous, the second smoetimes floriferous 
but more frequently sterile; bracts slightly spreading, scarcely 
keeled, the lobe straight (not falcate), ovate, mostly 0.55—0.65 mm. 
long and 0.25-0.3 mm. wide, acute and usually coarsely and irre- 
gularly toothed, the teeth sharp or blunt, rarely more than three or 
four, lobule in some cases distinct, 0.2-0.3 mm. long and 0.07 mm. 
wide with an acute apex, but usually narrower and sometimes © 
