MICROLEJEUNEA LUCENS 157 
at the base. The perianth, however, offers the best points of dif- 
ference ; in the new species this is much broader in the upper part 
than at the base and frequently flares out abruptly above the mid- 
dle, its keels also are sharper than in 7۰ cavifolia and sometimes 
shows rudimentary wings. In the United States Z. Americana 
seems to be confined to the bark of trees, while Z. cavıfolia is more 
at home on rocks, at the roots of trees, and creeping over other 
hepatics. 
L. Americana is a much paler and more delicate plant than 
Euosmolejeunea duriuscula. Its leaves spread more widely from 
the axis, and its lobules are relatively larger with their free mar- 
gins more involute, so that the apical teeth cannot usually be seen 
without dissection ; its underleaves also are larger and not cuneate 
at the base. In LZ. Americana, moreover, on account of its autoi- 
cous inflorescence, perianths are frequently developed, whereas in 
the other species they are extremely rare. 
L. Americana should hardly be confused with ۵ 
lucens. It is in the first place a much larger plant and has an 
autoicous inflorescence. It differs markedly also in the more 
conspicuous thickenings of its cell-walls and in its larger and 
broader underleaves, which are never sharply unidentate. on their 
lateral margins. 
Spruce's Z. fava, subsp. albida should apparently be referred to 
the present species, although his specimens are a little larger and 
were found on living leaves instead of on bark. Spruce afterwards 
recognized that the plant was specifically distinct from /. fava and 
distributed it in Hep. Spruceanae as a manuscript species. The 
writer has carefully compared these specimens with typical plants 
of L. Americana and finds no essential differences between them. 
16. Microlejeunea lucens (Tayl.) 
PLATE و21‎ Fics. 1۲-0 
Lejeunea cucullata Sull. Musc. Alleg. No. 274. 1845. Not 
ees, 
Lejeunea lucens Tayl. Lond. Jour. Bot. 5: 399. 1846. G. L. 
& N. Syn. Hep. 764. 1847. 
Lejeunea (Micro-Lejeunea) lucens Spruce, Hep. Amaz. et And. 
288. 1884. 
