tort] CURRENT LITERATURE 311 
increased internal pressure of gas which causes the streaming from the tube. 
This continues until the sphagnum is dry. 
OHNO conceived that the leaf of Nelumbo acts in a similar way, taking in 
the air thus by diffusion, which increases the internal pressure and leads to an 
extrusion at the central region where the texture is loose. He examined a 
number of other plants, but found no other case of a similar exchange.— 
WILt1aM CRocKER. 
Respiratory intensity.—Rosé"’ finds that the respiratory intensities of 
leaves, measured by cc. of CO, given off per hour per gram of green weight, 
varies with the illumination under which the plant is grown, and also with the 
stage of development of the plant. Pisum sativum and Teucrium Scorodonia 
were grown under cloth screens of various thicknesses. The light stopped 
by the screens was measured by means of a Vidal photometer. Rosé used 
four light intensities: V is full sunlight, IV is V—2x, III is V—16x, II is 
V—22x, x being the amount of light absorbed by a 5 mm. glass plate. Leaves 
were taken from the plants at different stages of their development, inclosed 
m. Aft 
leaves have developed, the maximum respiratory intensity was found to be 
at illumination V, and there is a gradual decrease to II; but in the later stages 
aximum is either at III, with a secondary increase at V, or the reverse. 
Rosé found that the structure of leaves developed under III and II was greatly 
modified. There was less lignified tissue and less cellulose; therefore, he 
thinks, there must be a greater amount of protoplasm and of carbohydrates 
ma given weight of leaf. There is less water in III than in II, therefore a 
Breater percentage of oxidizable substance per gram of green weight. So, 
the author says, the respiratory maximum is displaced from V, the place of 
greatest dry weight, to III, the place of greatest amount of oxidizable sub- 
stances. Teucrium Scorodonia, on the other hand, being a shade plant, has 
Its greatest respiratory energy at IV, with its greatest dry weight. 
The author’s explanations of his results are not convincing. Some quanti- 
tative determinations of the enzymes present would be of value. The results 
found for leaves under the different illuminations would have been more 
nearly comparable if the water variant had been eliminated by measuring the 
respiration for a unit of dry weight.—Sopu1a ECKERSON. 
Sporogenous tissue of Piper Betel.—The work of JonNson among P ipera- 
ceae is well known to morphologists, and he has now extended it by including 
Betel Monoicum,® a climbing Jamaican species with monosporangiate 
" Rosé, EpMonp, Energie respiratoire chez les plantes cultivées 4 divers éclaire- 
ments. Rev. Gén. Botanique 22: 385-398. 1910. : 
** JouNson, DuNncAN S., Studies in the development of the Piperaceae. I. 
The suppression and extension of sporogenous tissue in the flower of Piper Betel L. 
Var. monoicum C. DC. our. Exp. Zool. 9:715-749. figs. 71 (year of publication 
Not cited in separate). 
