24 
OHIO BIOLOGICAL SURVEY 
2. MUCILAGO Adanson. 
Muciiago spongiosa (Leysser) Morg. Plate IV, Fig. 4, 4a, 4b, and 4c. 
Sporangia combined into an aethalium which is covered by a fragile 
deciduous white crust of lime crystals. Sporangium wall frosted with 
crystals of lime. Capillitium of sparingly branched threads without lime. 
1. M. spongiosa (Leysser) Morg. Aethalium variable in shape 
and size; not more than 1cm. thick, formed of elongated confluent gray 
sporangia, the whole covered with a deciduous crust of crystals of lime. 
Sporangium wall membranous, frosted with lime crystals. Columella 
hollow, compressed, sometimes absent. Capillitium a branching network 
of stout purplish threads, with colorless ends which are attached to the 
sporangium wall or columella. Spores purple,very rough, 10 to ISmmm. 
in diam. 
Common. 
3. DIDYMIUM Schrader. 
Didymium clavus (A. & S.) Rost. Plate IV, Fig. 2. 
Didymium melanospermum (Pers.) Macbride. Plate IV, Fig. 3. 
Didymium squamulosum (A. & S.) Fr. Plate IV, Fig. 1, la, lb, and Ic. 
Sporangia stalked or sessile, sometimes forming plasmodiocarps. 
Sporangium wall covered with lime in the form of crystals which may be 
scattered loosely over the surface or combined into a brittle crust. 
Capillitium of sparingly branched threads without lime knots. 
A. 
A. 
Crystals of lime forming a brittle crust around sporangia, 
B. Crust smooth. 
C. Crust thin, dense, diderma like.. 
B. Crust thick but fragile. . 
B. Crust wrinkled . 
Crystals of lime loosely scattered on sporangium wall. 
D. Sporangia disc-shaped. 
D. Sporangia subglobose or plasmodiocarpous. 
E. Sporangia stalked. 
F. Stalk brown or black. 
G. Stalk dark brown, granular. 
H. Sporangia 0.7mm. in diam. 5. 
H. Sporangia 0.5mm. in diam. 
G. Stalk light brown, not granular, 
columella dark. 
F. Stalk orange, columella white. 
F. Stalk white. Forms of. 
E. Sporangia forming plasmodiocarps. 
I. Dehiscence of sporangia circumcissile. 
I. Dehiscence of sporangia irregular. 
.... 1. D. dijforme 
.. 2. D. crustaceum 
3. D. squamulosum 
.4. D. lavus 
D. melanospermum 
6. D. minus 
7. D. nigripes 
8. D. xanthopus 
3. D. squamulosum 
9. D. anellus 
3. D. squamulosum 
1. D. difforme (Pers.) Duby. Sporangia distinct, scattered or forming 
short plasmodiocarps, smooth, white sessile. Sporangium wall double, 
the outer of small crystals of lime forming a thin dense egg shell like 
