158 BOTANICAL GAZETTE | AUGUST 
The pycnidia occur on the diseased roots, and more abundantly on the lower 
part of the petioles and on the fruit, but rarely on the leaves. Cultures were 
obtained from hyphae invading the sound tissue of the roots and from spores. 
The colonies from both sources were similar, and many infection experiments 
with mycelium from both sources on sound roots were successful. The action 
of this species of Phoma in producing a scab and rotting of celery tubers is 4 
case analogous to the well-known root rot of sugar beets caused by another 
species of the same genus, Ph. Betae.—H. HAssELBRING. 
Treatment for smuts.—The usual methods of treating seed-grain for the 
prevention of smuts have not proved applicable in the case of the loose smuts 
of wheat and barley, since these fungi persist through the winter, not by 
means of spores adhering to the surface of the grain, but by means of a dormant 
mycelium in the interior of the seed. APPEL," following out the suggestion made 
by JENSEN at the time of the publication of his hot water treatment to use 4 
preliminary treatment with cold water for seed infected with these smuts, has 
worked out a more definite method founded on an experimental basis. APPEL 
assumes that, like the spores of smuts, the dormant mycelium will start into growth 
more readily than the infected seed, and that the active mycelium will be kill 
at temperatures which do not injure the seed. The experiments substantiate 
this belief. It is found that grain infected with Ustilago tritici or U. muda can 
be treated successfully by being soaked for six hours at 20~-30° C., and by being 
treated subsequently with hot water at 50-5 4° C., or by hot air ata corresponding 
temperature.—H. HAssELBRING. 
Dehiscence of anthers.—HANNIG *5 takes up what apparently he regards 
as a real difference between STEINBRINCK’s cohesion theory and SCHNEIDERS 
Schrumpfungstheorie for the explanation of the dehiscence of anthers. To the 
reviewer the two theories differ more in the degree of analysis than anything else, 
as he believes that this phenomenon must be in the last analysis found dependent 
upon the tensile strength of water. However, the author has done a real service 
in showing how the dehiscence is a genuine cohesion consequence. He has 
accomplished this by artificially causing dehiscence through the effect of dehy- 
drating solutions. He has shown that dehiscence will occur in a saturate a 
Phere if anthers are exposed to light which generates enough heat in the tissu® 
to reduce the vapor tension sufficiently to set up tension in the water contained i 
the membranes. Burcx’s notion that the nectaries withdraw water from 
membranes and hence cause dehiscence in a saturated atmosphere was not or 
firmed.—RaymonD H. Ponp, 
: “ici und 
14 APPEL, OTTO, Theorie und Praxis der Bekampfung von Ustilago tritict ue 
Ustilago nuda. Ber. Deutsch. Bot. Gesell. 27:606-610. 1910 . 
iss. 
*s Hannic, E., Ueber den Offnungsmechanismus der Antheren. Jahrb. Ww 
Bot. 47 2186-218. 1909. ; 
