6 
OHIO BIOLOGICAL SURVEY 
herbarium specimens. The most of the drawings are original. A very 
few of the figures are copied from Lister’s Mycetozoa, and from Macbride’s 
North American Slime-Molds. These are acknowledged in their 
appropriate place. The author prepared outline drawings of the spores 
and threads of the capillitium using the camera lucida, after which Miss 
Ruth Fullmer completed the drawings and prepared the plates under the 
author’s direction. 
THE MYXOPHYTA 
Simple plants destitute of chlorophyll. The few species of the 
Plasmodiophoreae live parasitically in the cells of the host, all others 
are saprophytes. The vegetative stage consists of a mass of naked 
cells called a plasmodium. At maturity the plasmodium produces a 
large number of spores. 
A. 
A. 
GENERAL KEY TO THE CLASSES, ORDERS, AND FAMILIES 
Parasitic; spores in masses in the cells of the host. 
Class I. Plasmcdiophoreae. 
A single family. Plasmodiophoraceae (P. 7) 
Saprophytic. 
B. Plasmodium of incompletely fused cells; spores masses without a wall; 
without zoospores. 
Class II. Acrasieae. (P. 8) 
B. Plasmodium of completely fused cells; zoospores present. 
Class III. Myxomycetae. 
C. Spores developed superficially upon erect branching sporophores. 
Sub-class I. Ceratiomyxeae. 
A single family. Ceratiomyxaceae. (P. 8) 
C. Spores in a sporangium with wall. 
Sub-class II. Myxogasterae. 
D. Spores dark (brown, black, or violet). 
E. Sporangium with lime; capillitium present. 
Order I. Physarales. 
F. Lime in the form of small round granules which may be found in 
any part of the sporangium. 
Family (1) Physaraceae. (P. 8) 
F. Lime in the form of crystals which are on the surface of the 
sporangium. 
Family (2) Didymiaceae. (P. 23) 
E. Sporangium without lime; capillitium solid. 
Order II. Stemonitales. 
G. Sporangia distinct, stalked. 
Family (3) Stemonitaceae. (P. 26) 
G. Sporangia united into an aethalium. 
Family (4) Amaurochaetaceae. (P. 32) 
D. Spores generally yellowish in color, never black. Lime absent. 
H. Capillitium wanting or imperfect. Order III. Liceales 
I. Sporangia distinct. 
J. f; ( : angium wall without definite thickenings. 
Family (5) Liceaceae (P. 33) 
J. Spa^aagium wall with thickenings in the form of a net or of ribs. 
Family (6) Cribrariaceae (P. 34) 
