er oe 
Studies in pyrophilous fungi—lll.* The viability of the spores of 
Pyronema 
FRED J. SEAVER 
(WITH PLATE 4) 
In the first paper of the present series, in attempting to impress 
upon botanists the value of Pyronema as a plant to be used in 
regular class study, it was stated that no data were at hand as to 
the length of time during which the spores of this fungus would 
keep their viability. As a knowledge of this point is of vital 
importance in determining whether the teacher is able to tide 
over this plant in the laboratory from year to year, it is deemed 
worthy of special study and mention at this time. 
As has been previously stated, when once this fungus has been 
cultivated it is comparatively easy to ‘get a catch’’ from the air 
by simply exposing properly heated soil and keeping it moist for 
afewdays. Especially is this true in greenhouses. To my knowl- 
edge, since this fungus has been under observation here, steamed or 
heated soil used for planting in the propagating houses of the 
New York Botanical Garden has never failed to develop the fungus. 
Some time ago the spores of the fungus were sent to Purdue Uni- 
versity for experimental purposes, and recently in a conversation 
with Dr. F. D. Kern he informed me that this fungus also now 
made its appearance in their greenhouse whenever heated soil was 
exposed. While the fungus may usually be obtained in this way 
when once it is started, this method is uncertain and the occur- 
rence of the plant is likely to be delayed when it is most needed. 
It is therefore better to develop and rely upon some more certain 
methods of securing and preserving it. 
During the present winter the fungus was desired for study in 
classes at Columbia University, and several pots of heated. soil 
were exposed to the air, as formerly, in the laboratories of the 
* Studies in pyrophilous fungi—II. Changes brought about by the heating of 
soils and their relation to the growth of Pyronema and other fungi, was published in 
Mycologia 2: 109-124. pl. 24-26. IQ10. 
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