76 METZGERIACEAE 
green, darkening with age or on drying, usually soft and flaccid 
when soaked out, furnished with a broad, for the most part indis- 
tinctly defined costa (0-16 cells in thickness), this passing gradu- 
ally into the wide unistratose somewhat sinuate-lobed margin ; root- - 
hairs springing from the costa, brownish, numerous. Monoicous 
or dioicous. Antheridia oval, short-stalked, immersed, usually 
singly, in loculi irregularly distributed along the dorsal surface of 
the costa. Archegonia in groups of 4-18, borne іп a pocket-like 
cavity near the apex of the costa, becoming dorsal by the subse- 
quent growth of the thallus, covered more or less by an involucre 
opening in front. Involucre at maturity of sporogonium a mere 
flap or scale at the posterior margin of the cavity or becoming 
tubular or forming a short and narrow ring, the margin crenulate 
or lacerate. Calyptra exserted from the involucre or included, its 
walls composed of several layers of cells. 
__ Sporogonium consisting of a spherical, light brown ог yellow- 
ish, 4-valved capsule on a very long delicate seta; capsule-wall bi- 
stratose, cells of the outer layer with yellowish-brown trigones or 
nodular thickenings, those of the inner layer with semiannular or 
imperfectly spiral thickenings (wanting or rudimentary in P. endivi- 
aefolia), “ elater-bearers ” and elaters both present, the former 20- 
100 in number, persistently attached to the base of the capsule, 2 
1—6-spiral, differing more or less in character from the true elaters ; 
the latter 2—4-spiral, mostly rather obtuse, often, together with the 
spores, remaining fora time clinging to the elater-bearers and form- 
ing a globular entangled massat the base of the valves. Spore 
very large, multicellular at the time of dehiscence, oval or ellipsoidal, 
punctulate. 
т. PELLIA МЕЕЗТАХА (Gottsche) Limpr.; Cohn, Krypt. Fl. Schles. 
1: 320. 1877. 
Pellia epiphylla, forma Neesiana Gottsche, Hedwigia, 6: 69. 
1867. 
did ; elater-bearers about 30, stout, conical- or 
beni 120-270 # x 18-36 и, mostly 3- ог 4-spiral, some 
spiral or annulate ; elaters strongly contorted, 2-, or more 
blunt- i 
times 
rarely, 
