horter or nearly wanting.

2. DIDYMIUM PROXIMUM, B. & C. Sporangium globose or depressed-globose,
the base more or less umbilicate, stipitate; the wall very thin and
pellucid, with a loose white covering of stellate crystals of lime, the
upper part breaking up and falling away. Stipe long, erect, tapering
upward, yellow-brown to reddish-brown, expanding at the base into a
small hypothallus; the columella central, white, turbinate, or discoid
turbinate. Capillitium of slender, colorless threads, radiating from the
columella, branching and often anastomosing. Spores globose, even, pale
violaceous, 8-10 mic. in diameter. Plate XII, Fig. 37.

Growing on old leaves, sticks, culms, etc. Sporangium .4-.6 mm. in
diameter, the stipe two or three times the diameter.

3. DIDYMIUM EXIMIUM, Peck. Sporangium depressed-globose, the base
umbilicate, sometimes very much depressed and also umbilicate above,
stipitate; the wall pale ocher or pale yellow, with a thin layer of
minute white crystals of lime, the upper part gradually breaking away.
Stipe long, erect, tapering upward, pale yellow-brown, darker below,
expanding into a small brown hypothallus; the columella central, large,
discoid, or sometimes rough and irregular, pale ochre or yellowish.
Capillitium of much-branched colorless threads, radiating upward and
downward from the columella. Spores globose, very minutely warted, dark
violaceous, 9-11 mic. in diameter. Plate XII, Fig. 38.

Growing on old leaves, sticks, etc. Sporangium .5-.6 mm. in diameter,
the stipe about twice the diameter.

4. DIDYMIUM MICROCARPUM, Fr. Sporangium small, globose, the base
slightly umbilicate, stipitate; the wall a dark-colored membrane,
covered with abundant snow-white crystals of lime. Stipe long, slender,
erect, delicately striate, yellow-brown to blackish in color, expanded
at the base into a small hypothallus; the columella small, globose,
sessile or substipitate, pale yellow-brown. Capillitium of pale brown
threads, somewhat branched and forming a loose net. Spores globose, very
minutely warted, violaceous, 6-7 mic. in diameter.

Growing on old wood, leaves, mosses, etc. Sporangium .4-.5 mm. in
diameter, the stipe two or three times as long. The species is more
particularly distinguished by its small spores.

5. DIDYMIUM MINUS, Lister. Sporangium depressed-globose, the base
umbilicate, stipitate, rarely sessile and plasmodiocarp; the wall a
dark-colored membrane with a thin layer of stel