DoRAN: ON THE GERMINATION OF FUNGOUS SPORES 317 
although older spores from the same fungus did germinate. All 
conclusions as to germination should be based upon the behavior 
of mature spores. 
It is possible by exercising care in obtaining spores to separate 
the mature from the immature to some extent at least. When a 
fungus has matured its spores, they are usually freed in such 
a way that they may be disseminated by the movement of air 
or water. So far as possible, the natural method should be 
duplicated in obtaining spores for experimental purposes. When 
a scab lesion on the fruit or leaf of the apple is washed, it is 
probable that only mature conidia and perhaps a few dead 
conidia of Venturia inaequalis are detached. But when a similar 
lesion on the fruit or leaf of the apple is brushed or scraped, it 
is probable that many immature conidia are also detached. In 
the case of all except the fungi having very short-lived spores 
the immature spores on a fresh lesion greatly outnumbered the 
dead spores. When the writer obtained conidia of Venturia 
tnaequalis by brushing apple scab lesions the relative number of 
conidia which were capable of germinating was only twenty-five 
as compared with the relative number of one hundred germinat- 
ing when the conidia were obtained by washing lesions with a 
stream of water from a pipette. When fungous spores are to be 
obtained for germination studies they should be freed from the © 
host as gently as possible and in as nearly as possible the same 
way in which they would be removed in nature. In this connec- 
tion it is interesting to note that Jones (5) found that the 
ascospores of Pseudopeziza Trifolii and P. Medicaginis germinate 
readily when they are discharged naturally but not when they 
are crushed out of the ascus. 
Some attention has been given to the later maturing of spores 
which were detached from the fungus while still immature. 
Schaffnit (6) is of the opinion that unless fungous spores are 
internally mature before they are detached from the fungus, 
they never gain power to germinate. But the results of Melhus 
and Durrell (7) indicate that some urediniospores can mature 
after being detached from the furigus. 
With the exception of the spores of Botrytis cinerea, all the 
fungous spores studied by the writer were —— killed if 
detached when immature. 
It is possible in some cases to distingiush between mature and 
immature spores by their relative position in the fruiting parts 
