476 
Journal of Agricultural Research 
Vol. XXX, No. 5 
examination of the wilting plant showed 
that the typical mycelial strands of 
yellowish hyphae of Ozonium extended 
from the soil up the stem several inches 
and there began to change into a subic- 
ulum which surrounded the stem and 
formed a hymenium with the typical 
spines of a species of Hydnum, as illus¬ 
trated in the accompanying plate (pi. 1). 
The organic connection between the 
typical Ozonium hyphae and those of 
the Hydnum appeared to be unques¬ 
tionable. 
In order to complete the proof of the 
genetic relationship of the two forms, 
efforts were made to grow the fungus 
from the Hydnum. Unfortunately, 
however, all of our efforts in this 
direction failed. 
mycelium has a general similarity to 
the various sterile mycelia described by 
Persoon under the generic name Fibril- 
laria, some of which are known to 
belong to hymenomycetous fungi. 
Being unable to find named speci¬ 
mens or a description to apply to this 
Hydnum, a description and illustration 
are given which it is hoped will make 
it possible for mycologists and patholo¬ 
gists who may encounter the fungus to 
recognize it. 
Hydnum omnivorum n. sp. 
Subiculum effuse, thin, readily sep¬ 
arating from the substratum, subgelat- 
inous, pale yellow, margin floccose, 
fibrillose-fimbriate, white; spines slen¬ 
der, acute, somewhat crowded, 2-3 
Fig. 1 .—Phymatotrichum omnivorum: Conidial stage of the fungus, showing mode of conidial production 
(after Duggar) 
Conidial forms similar to the Phyma¬ 
totrichum stage of this fungus are 
known to occur among the Hymeno- 
mycetes and there is nothing in this life 
history which conflicts with our present 
knowledge of the subject. 
The Hymenomycete, Tomentella 
granulata , according to Brefeld 6 has a 
conidal form very similar to that of 
Ozonium omnivorum. The Ozonium 
mm. long, orange-buff to light orange- 
yellow (Ridgway). No spores found. 
Conidial stage (Phymatotrichum om¬ 
nivorum). Hyphae forming a loose 
layer on the surface of the soil in areas 
where the root rot has killed the plants; 
fertile hyphae arising irregularly from 
the mycelium, simple or forked; conidia 
numerous, sessile, borne on the irregu¬ 
larly swollen clavate or subglobose 
6 Brefeld, O. basidiomyceten hi. p. 11-12, tab. 1, fig. 16. 1889. (In his Untersuchungcn aus dem 
Gesammtgebiete der Mykologie, Heft 8.) 
EXPLANATORY LEGEND FOR PLATE 1 
Life history of Ozonium omnivorum Shear 
A. —Hyndum omnivorum. Natural size on wilting Maclura 
B. —Portion of the fungus, with spines enlarged 20 diam. 
