34 
OHIO BIOLOGICAL SURVEY 
2. ORCADELLA Wingate, 
Orcadella operculata Wing. Plate VI, Fig. 6. 
Sporangia suhglobose, stalked; opening by a distinct membranous lid. 
1. O. operculata Wing. Sporangia scattered, urn shaped, or 
subglobose, very minute, 0.1 to 0.3mm. in diam., dark brown, with a 
yellow glossy convex lid. Stalk cylindrical, furrowed, dark, filled with 
refuse matter. Spores nearly colorless, smooth, 8 to llmmm. in diam. 
This very minute species has not been reported from Ohio. Since the 
type material was collected in Pennsylvania we should expect the species 
to occur in the state. It has probably been overlooked on account of its 
minuteness. 
FAMILY 6 . CRIBRARCAEAE. 
Sporangia distinct, stalked. Sporangium wall with thickenings in the 
form of a net or ribs. 
KEY TO THE GENERA OF CRIBRARIACEAE. 
A. Sporangium wall with thickenings in the form of ribs. 1. Dictydium 
A. Sporangium wall with thickenings in the form of a net. 2. Cribraria 
1. DICTYDIUM Schrader. 
Dictydium cancellatum (Batsch) Macbr. Plate V, Fig. 8. 
Sporangia distinct, stalked, globose. Sporangium wall consisting of 
parallel ribs extending from the base nearly to fhe apex and connected by 
slender transverse threads; the thin wall connecting the threads evanescent. 
1. D. cancellatum (Batsch) Macbride. Sporangia gregarious, globose, 
0.5 to 0.7mm. in diam., dark brown or purple, stalked, cernuous. Sporang¬ 
ium wall of numerous rigid longitudinal ribs connected by slender 
transverse threads, with the thin wall between the threads early deciduous. 
Sometimes the ribs are replaced by a net in the upper part of the 
sporangium. Stalk slender, subulate, bent or twisted, dark brown. 
Spores purple red, minutely roughened, 5 to 7mmm. in diam. 
Abundant everywhere on rotten wood. 
2. CRIBRARIA Persoon. 
Cribraria tenella Schrad. Plate V, Fig. 7. 
Sporangia globose, stalked. Sporangium wall forming a cup at the 
base and above a net of delicate threads with expanded nodes. The thin 
wall connecting the threads being early deciduous. 
A. Net without expanded nodes. 1. C. argillacea 
A. Net with expanded nodes. 
B. Sporangia brown. 
C. Nodes with rounded outline. 
D. Cup wanting or rudimentary. 
E. Cup replaced by ribs. 
E. Cup replaced by the net. 
2. C. dictydioides 
3. C. microcarpa 
