oil 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Movements of the Flower and Fruit of Erodium.* — Dr. R. Cobelli 
finds that from the period of the opening of the flower to the ripening 
of the seeds, there occur, in Erodium gruinum, movements of the calyx, of 
the upper part of the flower-stalk, and of the mericarps. The sepals, 
at first erect, afterwards open to a nearly horizontal position, and then 
again close after the petals have dropped. The upper portion of the 
flower-stalk goes through various movements, which facilitate the pollen 
reaching the stigma in the same flower. No pollinating insects were 
observed on the plant, and it appears to be self-fertilized. The column 
turns on its axis to the extent of about 90°, carrying with it the beaks 
of the mericarps which remain attached to the column by their apices. 
The mericarps ultimately become detached from the* column with such 
force that their elasticity causes them to be thrown to a distance of as 
much as 50 cm. from the plant. 
Movements of the Leaves of Porlieria.f — Sig. G. Paoletti de- 
scribes in detail the structure of the leaves of Porlieria hygrometrica 
(Zygophyllaccse), and the phenomena attending their periodical move- 
ments. The lower portion of each leaf-stalk is expanded into a “ primary 
motor node,” a swollen mass of tissue with from ten to fifteen transverse 
furrows, and each leaflet has also its “ secondary motor node.” In each 
primary motor node are conducting bundles and a conducting paren- 
chyme. 
The movements of the leaves are nyctitropic ; there are no true 
hygrometric movements, as the specific name of the plant would seom to 
imply. In the same leaf all the leaflets pass from the diurnal to the 
nocturnal, and from the nocturnal to the diurnal position, at nearly the 
same time. The youngest leaves attain their position of fullest ex- 
pansion about mid-day ; all the others at from 7 to 7 * 30 a.m. 
The cause of the nyctitropic movements in this, as in other plants, 
is the unequal stretching of the upper and under halves of the motor 
nodes, in other words, a periodical variation of volume in the cells of 
which the upper and under surfaces are composed ; there is no question 
of an unequal growth, as in movements of nutation. The cause of this 
change of volume lies most probably in the protoplasm and in the 
osmotic properties of the cell-sap. The cells which display this 
property belong only to the outer portion of the cortical paren chyme, 
which constitutes therefore a motor system in each motor node ; the 
inner portion of the cortical parenchyme, the central parenchyme, and 
the conducting bundles, constituting an axial passive system, which 
assists, by its flexibility, in the nyctitropic movements. 
Photographic Representation of the Movements of Plants.^ — 
MM. Dewevre and E. Bordage point out the inadequacy of Darwin’s 
method of observing the movements of plants, and describe an appa- 
ratus of their own contrivance which combines a graphic and a photo- 
graphic representation. 
Observations made in this way on climbing plants (Humulus Lupulus, 
Ipomsea purpurea , Convolvulus sepium ) showed that the movements of 
* Nuov. Giorn. Bot. Ital., xxiv. (1892) pp. 59-64 (1 pi.). 
t Tom. cit., pp. 65-91 (5 pis.). 
X Rev. Gen. de Bot. (Bonuier), iv. (1892) pp. 65-78 (8 figs.). 
