ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
331 
Distribution of Aluminium in Plants.* * * § — From a series of analyses 
made by MM. Bertbelot and G. Andre of the tissues of a variety of 
plants, chiefly herbaceous, it appears that aluminium exists chiefly in 
the roots, in conjunction with phosphoric acid. The quantity which 
reaches the leaves is exceedingly small, in the case of the lime nearly 
infinitesimal. Aluminium phosphate may occur in solution in the 
presence of citric and tartaric acid. 
(3) Structure of Tissues. 
Schizo-lysigenous Receptacles for Secretions.f — Herr W. Sieck has 
investigated the mode of formation and structure of these receptacles, 
chiefly in the Rutaceae. He finds that the oil- cavities arise from a 
specialised mother-cell or idioblast, from which a special tissue is 
developed which is subsequently resorbed. The central cells then part 
from one another, forming a schizogenous cavity. The cell-walls which 
face the canal present the character of mucilage- membranes. The 
secretion is formed in the cell-wall, and gradually collects in the side 
which faces the intercellular space, this portion bulging out so as to 
form a cap. The oil accumulates in this cap ; the outer layer of the 
membrane bursts, and the oil passes into the canal ; the inner layer also 
bursts, and the protoplasts are exposed. In the resin-canals of the 
Anacardiaceae, the lysigenous enlargement of the receptacle is effected 
by the gelatinising of the intermediate cell-walls. Except under 
pathological conditions, no purely lysigenous secretion-receptacles occur 
in the Rutaceae, Simarubaceae, Anacardiaceae, Gynometraceae, Diptero- 
carpaceae, or Hamamelideae. 
Laticiferous System of the Convolvulacese.if — Dr. F. Czapek states 
that in all the genera of Convolvulaceae, except Dichondra, the laticiferous 
tubes have septa which are not resorbed. The laticiferous cells originate 
in the embryo at the same time as the rudiments of the vascular bundles. 
Those of the hypocotyl and of the cotyledons form a connected system 
with which those of the epicotyl only subsequently come into connection. 
In the epicotyl their development coincides in time and place with that 
of the leaf-trace bundles. In Dichondra the laticiferous receptacles are 
unseptated, and differ from the adjoining cells only in their thicker walls. 
With regard to their physiological purpose, the laticiferous tubes of the 
Convolvulaceae form a conducting system, the function of which appears 
to cease with the completion of the growth of the plant. 
Deformations caused by Fungi.§ — Mr. W. G. Smith describes the 
structure of the deformations in the shoot and leaf caused by species of 
Exoascus. In the shoot the chief change is in the parenchymatous cells, 
which increase in size and divide. There is less change in the vascular 
bundles ; though there is a tendency to a weakening of the scleren- 
chymatous elements. The phloem-elements are richer in protoplasm. 
The tracheae increase in number, but are less developed. The libriform 
* Comptes Rendus, cxx. (1895) pp. 288-90. 
t Jahrb. f. wiss. Bot. (Pfeffer u. Strasburger), xxvii. (1895) pp. 197-242 (4 pis.). 
Cf. this Journal, ante , p. 190. 
I SB. K. Akad. Wiss. Wien, ciii. (1894) pp. 87-121 (5 pis.). 
§ Forstl. Naturw. Zeitsckr., 1894, pp. 420, 432, 473 (1 nb and 1 fig.).' See 
Hedwigia, xxxiv. (1895), Rep., p. 20. 
