йе. MARCHANTIACEAE 
cending when dry, furnished with a unistratose border 1—3 cells 
in width; costa (exclusive of air-chamber layer) 15-20 cells in 
thickness, gradually attenuate to the wing on either side. Мопоі- 
cous.  Antheridia immersed in the thallus just posterior to 
the base o the % branch, in a single or irregularly double, 
often much elongated, row, each completely filling the loculus at 
maturity and adnate to its walls, ostioles papilliform, inconspicu- 
ous. О branch from the apex of the costa. Peduncle slender, 
naked throughout, pale or sometimes brownish-purple below, 
irregularly sulcate, the dorsal (posterior) face without assimila- 
tive tissue, the ventral (anterior) face with a single root-hair fur- 
row.*  O receptacle subhemispherical in early stages, soon be- 
coming circular-disciform, lightly convex and somewhat papulose 
above, plane and naked beneath, much attenuated toward the cre- 
nate margin, furnished with 3-7 (commonly 5) radiating root-hair 
canals in communication with the root-hair furrow of the peduncle, 
these reaching a little more than halfway to the margin, surrounded 
by a compact tissue, and, after drying, sometimes appearing costa- 
like; air-chambers large, in a single layer, with dolioform stomata ; 
archegonia in groups of four, alternating with the root-hair canals, 
one archegonium of each group (very rarely two) producing a 
sporogonium. Sporogonia (3-7, usually 5) occupying ellipsoidal 
radiately disposed loculi reaching commonly a little more than half 
the distance to the periphery of the receptacle, the margins of the 
loculus early connivent and enclosing the capsule, separating later 
by an elongated radial cleft, this finally gaping and widely expos- 
ing the capsule, the lips becoming membranous-scarious, remain- 
ing somewhat elevated, and functioning as the only involucre. 
Calyptra inconspicuous. Capsule nearly spherical or oblately 
ellipsoidal, the apical third or fourth of its wall consisting of two 
layers of cells and falling away as an operculum in dehiscence, the 
wall otherwise unistratose, the cells without annular or spiral thick- 
enings, those of the operculum with the walls slightly thickened 
at the angles. Seta very short, foot bulbous. Spores brown, 
more or less distinctly tetrahedral, irregularly areolate-lamellate, 
with a pellucid margin.  Elaters attenuate, contorted, often 
branched, closely 2-(3-) spiral. 
The only recognized species is 
our investigations upon Californian material and the Hookerian type, we have as yet 
been unable to find any peduncle with more than one furrow containing root-hairs. 
