, 
1906] FULTON—CHEMOTROPISM OF FUNGI 85 
of sporangiophores, especially of certain Mucorineae, have been 
carefully studied. 
A negative hydrotropism for the sporangiophores of Phycomyces 
nitens was first experimentally established by WoRTMANN (35), and 
was later confirmed by the more extended studies of- ERRERA (10) 
and of STEYER (30). MotiscH (22) showed that the sporangio- 
phores of Mucor stolonifer and Coprinus velaris are negatively hydro- 
tropic; while Kress (17) made similar observations for Sporodinia 
grandis, which FaLcK (12) has failed to confirm. 
WorTMANN (35) observed what he supposed to be negative 
hydrotropism in the case of the mycelium of Mucor sp., which would 
grow towards water, but would turn aside and branch profusely 
on reaching its surface. The conditions of experiment were such 
as to make his explanation of the phenomenon doubtful. STEYER 
(30) concludes that moisture plays an unimportant réle in deter- 
mining the growth and spreading of the mycelium of Phycomyces 
nitens. 
JONsson (15) grew mycelia of Mucor stolonijer, Phycomyces 
nitens, and Botrytis cinerea on sloping filter-paper strips having 
their two ends dipped in vessels of water at different levels. Phy- 
comyces and Mucor showed negative rheotropism under these con- 
ditions, while Botrytis showed positive rheotropism. 
HorMEISTER (14), WORTMANN (35), Dietz (7), KLEBs (17), 
and STEYER (30) have established for various Mucoraceae a negative 
reaction of their sporangiophores to gravity and to strong light; 
but there is a positive reaction to contact and to moderate intensi- 
ties of light. 
Kwny (18) holds that gravity has no effect upon the growth of 
the mycelium of Mucor mucedo, M. stolonijer, Trichothecium roseum, 
and Eurotium repens. Muyosut (20) concludes from his tests that 
neither gravity, light, contact, nor moisture affected the turning 
of the six fungi used in his investigations. STEYER (20) in his study 
of the reactions of Phycomyces, found that the mycelium is indifferent 
to light, contact, and gravity. 
MATERIALS AND GENERAL METHODS. 
To a greater or less extent fourteen species of fungi have been 
used; these, with respect to nutritive adaptations, may be classed 
as follows: 
