1912] CURRENT LITERATURE 363 
develop first as confervoid bodies, growing by a single apical cell. This body 
then becomes monostromatic, with a monosiphonous stipe. The two cells 
situated side by side at the same level below the apical cell initiate the mono- 
stromatic blade, and this blade becomes distromatic at base, and at the same 
time the monosiphonous stipe becomes polysiphonous. A new meristematic 
tissue appears at the transition region between blade and stipe. The growt 
both in length and breadth is due to the apical and stipo-frondal growth up to 
a certain period. The apical growth gradually diminishes and finally ceases, 
and then erosion of the apex of the blade follows. A single precortical layer 
of large parenchymatous cells is developed at the transition region between the 
already existing two layers. The hyphal cells are formed as the precortical 
layer becomes doubled, and the expansion of their distal ends into a trumpet 
shape takes place at the intercellular spaces. The ribs and meridional region 
are formed by special thickening of the cortical layers. The dorsiventrality 
of the lamina, if<it exists, is indicated simultaneously with the formation of 
these parts. The cryptostomata in the Laminariaceae do not originate from 
a single cell—S. YaMANOUCHI. 
Geotropism.—ArpAp PaAx™ finds that reduction of the air pressure 
lengthens the geotropic reaction and presentation times in the root of Phaseolus 
vulgaris. The presentation time was 6 minutes at one atmosphere; 20 minutes 
at 0.74; 35 minutes at 0.21; and 70 — ato.o8. The reaction time was 
found markedly variable when all control ditions were constant. From 
the average of many mcurie the wittior finds that if at one atmosphere 
the reaction time is considered as 1, at o.74 atmosphere it is 1.09; at 0.34 
atmosphere 1.39; at o.21 atmosphere 1.60; and at 0.08 atmosphere 2. 20. 
It is interesting to see what slight reductions in pressure cause a lengthening 
of these critical times. It is well known that the respiratory intensity is not 
cut until the pressure is reduced to a much greater degree. If the effects here 
are due to the reduced oxygen pressure, as is assumed, one sees what a complex 
réle oxygen plays in the organism, the several functions apparently having very 
different critical pressures. The author concludes that the lengthening of the 
reaction time is due to the sum of the effect of reduced pressure upon the sen- 
sory and motor phases and to the telescoping of these phases.—WILLIAM 
CROCKER : 
Formaldehyde and green plants.—Grare* finds etiolated plants or 
non-chlorophyll parts of green plants very sensitive to vapors of formaldehyde, 
especially if the cultures are illuminated. The chlorophyll-bearing parts 
(Phaseolus vulgaris) are not injured by concentrations as great as 1.3 per cent 
™4 Pad, Arpdp, Analyse des geotropischen Reizvorgangs mittels Luftverdiinnung. 
Jahrb. Wiss. Bot. 50:1-20. 1911. 
** GRAFE, VIKTOR, Untersuchungen iiber das Verhalten eee — zu 
Gasformigen Formaldehyde. Ber. Deutsch. Bot. Gesells. 29: 19-26. 1 
