78 METZGERIACEAE 
heteromorphic, dentate scales, in an irregular row on each side of 
the costa, attached by the posterior margin or near the middle 
with the margins free. On the ventral surface, also, are small, 
hollow, subspherical organs, the “ leaf-auricles,’’ usually two near 
the base of each lateral lobe, their cavities commonly soon occu- 
pied by colonies of Nostoc.* Marginal cells of the lateral lobes 
20-30 и, oblong, quadrate, or oval, each often with a salient point, 
remaining cells of lobe 30-60 и, rhombic-hexagonal, surface cells 
of the axial region more elongated. Gemmae of two kinds; one 
borne in dorsal flask-shaped receptacles formed out of the sub- 
stance of the apex of the costa and appearing single, paired, or 
in threes, according to the development of the branch-system, fur- 
nished at maturity with a long slender neck (1-2 mm. x . 1 7—.3 mm), 
Ше neck-wall 2-4 cells in thickness, the gemmae flattened-oval, 
90-135 #4, 3-5 cells wide, 2 cells thick or unistratose at margin, 
borne on slender hyaline pedicels arising from the base and sides 
of the receptacle, the pedicels accompanied by short, clavate, uni- 
cellular trichomes ; second form of gemmae on the dorsal surface 
of the younger portions of the plant, scale-like, stellate or coarsely 
dentate, of a single layer of cells near their margin, of two or more 
layers toward the middle. Dioicous. ( plants smaller; anthe- 
ridia several, immersed singly in a row along the dorsal surface of 
the costa. Archegonia numerous, on dorsal surface of the costa 
‘toward the apex, the single fertilized archegonium becoming, by 
the arching over of the adjacent parts, completely enclosed within 
а cylindrical or clavate inflation of the costa, this 3-4 mm. 1" 
length, directed forward, finally ruptured at the anterior end by 
the elongating sporogonium, and functioning as an involucre. 
Calyptra light-colored, membranous. Capsule oval, dingy brown, 
1-1 14 mm. long, dehiscing by 4 (4-6) valves, inner surface with 
annular or spiral thickenings, the outer surface showing brownish 
nodules in the radial walls; seta rather thick, 1 4-2 cm. long. 
ie жы somewhat angular, 38—50 и, slightly granulate 
g with the elaters in a central globular mass. ate 
‚200—300 их 10-14 и, with two spiral bands, these often becoming 
paired by splitting. 
The only known species is 
I. BrasiA PUSILLA L. / с. 
Jungermannia Blasia Hook. Brit. Jung. p/. 82-84. 1816. 
*'The 
perhaps serving as reservoirs of moisture ( Goebel, in Schenk's Handbuch der 
2: 4 
Ме АА The colony is surrounded ventrally by a single layer 
penetrated by a branching tube which springs from the wall of the cavity. 
Nostoc colonies are thought to live in symbiotic relations with the D 
, 
n 
