The Morphology and Physiology of the 
Genus Eidamia. 
BY 
A. S. HORNE, D.Sc., and H. S. WILLIAMSON, B.Sc. 
(From the Department of Plant Physiology and Pathology , Imperial College of 
Science and Technology .) 
With twenty-three Figures in the Text. 
Contents. 
PAGE 
I. Introduction.393 
II. Morphological Characters.394 
III. Physiological Characters.401 
A. Growth in Carbohydrate, Protein, and Asparagin .... 401 
B. Growth Limitation in Relation to Hydrogen-ion Concentration . 408 
C. Utilization of Acid.411 
D. Growth on Agar with Organic Acid in Various Concentrations . 412 
E. Growth on Potato Extract Agar with Organic Acid in Various 
Concentrations.415 
F. Growth in Equimolar Solutions of Organic Acids . . . .421 
G. Colour Production in Media containing Gallic or Tannic Acid . 424 
H. General Conclusions on Growth in Relation to Acids . . .425 
IV. Systematic Position and Specific Descriptions.426 
V. Summary. 431 
I. Introduction. 
T HE genus Eidamia was founded by Lindau ( 11 ) to include fungi which 
bear a general resemblance to Aspergillus , but differ from it in possessing 
not only conidia but also spores of a second type. These spores are larger 
than the conidia and are borne singly on lateral branches as in certain 
species of Monosporium. This genus has hitherto consisted of one species 
only, Eidamia acremonioides , Harz, originally described as Monosporium 
acremonioides by Harz in 1871, and as Papulaspora aspergilliformis by 
Eidam (6) in 1883. 
Comparatively recently the writers, working concurrently on different 
problems, obtained two fungi which, although differing from one another and 
from Eidamia acremonioides somewhat widely, nevertheless agree with 
Eidamia in possessing spores of the Monosporium type in addition to their 
[Annals of Botany, Vol. XXXVII. No. CXLVII. July, 1923.] 
