504 BOTANICAL GAZETTE [DECEMBER 
Occasionally flowers are also found showing a tendency to become bisporan- 
giate—J. M. C 
- Physiology of parasitism.—Brown” has begun a much needed investigation 
of the physiological relation of host and parasite, his first paper dealing with 
Botrytis cinerea. From the germ tubes of this fungus he succeeded in obtaining 
a very powerful extract, whose action on cell walls results in the disintegration 
of tissue, and whose action on the protoplasts produces death. This extract 
loses its “lethal power” by heating, by mechanical agitation, and by neutrali- 
zation with an alkali. Neither oxalic acid nor oxalates are accountable for 
the toxicity of the extract, which the author concludes must be due to the 
presence of a substance of colloidal nature. The only active substance dis- 
covered was an enzyme which was thought to be responsible for the lethal 
action of the extract. The multiplication of such investigations will result in 
some progress in knowledge as to the nature of immunity and susceptibility.— 
JM. C. 
Morphology of Ephedra helvetica.—In a thesis presented for the doctorate 
of science at the University of Geneva, SIGRIANSKI” has reviewed and rein- 
vestigated Ephedra helvetica. ‘Two new facts are reported. The hypodermal 
rc i i 
deeply within the nucellus. The figures which aus this situation will not 
entirely satisfy a critical investigator. A second and most important fact is 
that the four megaspores are all functional, the wall of the megaspore mother 
cell being the embryo sac wall, as in Lilium and some other angiosperms. It 
would be most interesting to know with certainty whether Welwitschia and 
Gnetum have attained the Lilium level in this respect.—W. J. 
Jurassic wood.—Miss HotpENn* has described a new species of Metace- 
droxylon from the Jurassic of Scotland, under the name of M. scoticum. It isa 
good illustration of the merging of araucarian and abietinean characters 
during the Jurassic, since it is araucarian in the pitting of the tracheids, and 
abietinean in the pitting of the rays. It differs from M. araucarioides only in 
the absence of pits on the tangential walls of the tracheids and in the biseriate 
character of the rays.—J. M. C 
19 BRowN, WILLIAM, Studies in the physiology of parasitism. Ann. Botany 29: 
313-348. 1915. 
2 SIGRIANSKI, ALEXANDRE, Quelques observations sur l’Ephedra helvetica Mey. 
pp. 62. figs. 74. Geneva. 1913. 
* HotpeN, Ruta, A Jurassic wood from Scotland. New Phytol. 14:205-209- 
pi. 3. IQTS. 
