508 JUNGEKMANNIACEAE. 



5. LEJEUNEA Libert, Ann. Gen. Sci. Phys. (Brux.) 6: 372. 1820. 



Stems prostrate, small, irregularly branched, the branches as in Radula; 

 rhizoids springing from the bases of the underleaves. Leaves complicate- 

 bilobed, the dorsal lobes larger than the ventral, incubous, attached by a long 

 line, ovate to obovate, rounded to obtuse at the apex, entire or slightly crenulate ; 

 lobule when well developed inflated, acute, bearing a hyaline papilla at the base 

 of the apical tooth on the side next to the stem; leaf -cells thin-walled but 

 sometimes with small trigones. Underleaves ovate to orbicular, bifid, the divi- 

 sion mostly entire or crenulate. Antheridia borne or in pairs in the axils of 

 saccate bracts, the latter in more or less elongated androecia. Archegonia 

 borne singly on branches variable in length with one or two subfloral innova- 

 tions, the bracts with plane lobules, bractole bifid. Perianth inflated, five- 

 keeled, abruptly narrowed to a distinct tubular beak. [Commemorates A. L. S. 

 Lejeune, Belgian botanist.] Nearly 200 species, mostly tropical. Type species: 

 L. cavifolia (Ehrh.) Lindb. 



Lobule about 0.2 mm. long ; keels of perianth smooth or nearly so. 1. L. flava. 

 Lobule about 0.1 mm. long ; keels of perianth distinctly crenulate. 2. L. glaucescens. 



1. Lejeunea flava (Sw.) Nees, Naturges. Eur. Leberm. 3: 277. 1838. 



Jugermannia flava Sw. Prodr. 144. 1788. 



Plants pale to yellowish green, scattered or growing in depressed mats. 

 Leaves imbricated, the dorsal lobe widely spreading, ovate, about 0.5 mm. long, 

 rounded to obtuse at the apex ; lobule inflated, ovate, more or less involute, apex 

 tipped with a single blunt cell; leaf-cells thin-walled but usually with distinct 

 trigones, averaging about 23 /* in the middle of the lobe; underleaves usually 

 subimbricated, orbicular, plane, bifid about one half with the segments usually 

 sharp-pointed and the sinus narrow; inflorescence autoecious; female inflores- 

 cence borne on a more or less elongated branch with one or two subfloral inno- 

 vations; bracts a little larger than the leaves; bracteole free, ovate; perianth 

 obovoid, the keels rounded in the upper part, smooth. 



On bark, Waterloo and Maidenhead Coppice, New Providence : North Carolina 

 to Florida and Texas ; Ireland ; Australia ; widely distributed in tropical regions 

 throughout the world. YELLOW LEJEUNEA. 



2. Lejeunea glaucescens Gottsche, in G. L. & N. Syn. Hep. 378. 1845. 



Plants pale to bright green, scattered or growing in thin, depressed mats. 

 Leaves subimbricated, the dorsal lobe widely spreading, ovate, about 0.7 mm. 

 long, -usually broad and rounded at the apex ; lobule inflated, triangular-ovoid, 

 involute, apex tipped with a single blunt cell; leaf-cells thin-walled and usually 

 without trigones, averaging about 33 X 25 ^ in the middle of the lobe; under- 

 leaves distant, orbicular, plane, bifid about one third with rounded or obtuse 

 lobes and a narrow sinus; inflorescence autoecious; female inflorescence borne 

 on a more or less elongated branch with a single subfloral innovation; bracts 

 shorter than the leaves, the lobule pointed; bracteole slightly connate, ovate to 

 obovate ; perianth obovoid, the keels rounded above, minutely crenulate. 



On bark, Great Bahama and Cat Island : Florida ; tropical America ; range not 

 definitely known. The Bahamian specimens are not very well developed but seem to 

 be referable to this species. GRAYISH LEJEUNEA. 



