162  LEJEUNEAE OF THE UNITED STATES AND CANADA 
0.25 mm. wide, rounded or very obtuse at the apex, margin as in ^s 
leaves but usually more sinuate, lobule mostly ligulate, rounded 
at the apex, varying to subacute, 0.3 mm. long, 0.1 mm. wide, 
keel wingless or nearly so; bracteole free, ovate from an ab- 
ruptly contracted base, 0.5 mm. long, 0.35 mm. wide, bifid about " 
one third with sharp, more or less contorted segments and narrow ; 
sinus, margin as in bracts : perianth and 4 inflorescence unknown. _ 
. On bark. Big Frog Mountain, Tennessee (A. Ruth), the 
type-locality. Sm 
Microlejeunea Ruthii is closely related to the European M. 
ulicina (Tayl), agreeing with it in its general habit and dioicous 
inflorescence. In M. ulicina, however, the lobes of the leaves 
are more convex and tend to be more or less pointed, the leaf- 
cells have thinner walls, and the underleaves are more deeply 3 
divided, the narrower divisions being as a rule only two cells wide : 
at the base. The bracts also are more distinctly winged at the 3 
keel, their lobes are more pointed and are often denticulate on the T 
margin, while the bracteole is narrower. a 
Although firmer in texture than M. /ucens and darker in color, p. 
M. Ruthii resembles this species in several respects. It maybe 
distinguished by the less widely spreading lobes of its leaves, by | 
its slightly smaller cells with thicker walls, and by its broader 
underleaves, which have broader segments and are never uniden- 
tate on the sides. The ¢ inflorescence also is borne on a leading | 
branch instead of on a short branch as is usual in M. ۵۰ 
18. Microlejeunea Cardoti (Steph.) 5 
Lejeunea (Micro-Lejeunea) Cardoti Steph. Bot. Gazette, 17: 
1892 | 
Dark green, loosel 
0.03 mm. in diameter, copiously and irregularly branched, the . 
branches widely spreading : 
loosely imbricated, the lobe obli 
long, 0.17 mm. wide, plane, apex broad and rounded 
volute to apex, then passi i ۱ 
apex tipped with a single projecting, straight or outwardly curved 
