304 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
composed of the sieve-tubes and the traces of the cambiform cells ; 
(2) The absorption- system, consisting of the companion-cells, whose func- 
tion is to take up the substances transported in the sieve-tubes, or to 
carry formative materials from the storing tissue, and to transfer them 
to the sieve-tubes ; (3) The storing system, represented by the longitu- 
dinal parenchyme-traces of the leptome and by the leptome medullary 
rays, which store up in themselves the assimilated substances. The 
characteristic function of the leptome of the l^igher plants is the trans- 
port of both nitrogenous and non- nitrogenous formative materials ; the 
conduction of the carbohydrates and oils taking place chiefly through 
the sieve-tubes and cambiform traces. 
Formation of Periderm and Epiderm.* — From a series of experiments 
made by imbedding in gypsum on a number of different plants, Herr H. 
Tittmann finds a marked difference in their power of regeneration 
between the periderm and the epiderm. A regeneration of the periderm 
was found to take place in many cases under favourable circumstances, 
but not of the epiderm. The cuticle is, however, frequently re-formed 
afresh. A power of regenerating the layer of wax exists in some plants, 
but not in others. The process is independent of light. 
Cork-Growths.f — Sig. E. Matteucci discusses the various kinds of 
cork-growth found in the leaves and other organs of plants, and classifies 
them, after Bachmann,J under two types, passing into one another by 
insensible gradations. In the first the cork-growth forms a prominent 
excrescence on the surface of the leaf, the cells being arranged in regular 
rows, with their walls parallel to the surface of the leaf. In the second 
type it extends deeper into the tissues of the leaf, and is of a spherical or 
hemispherical form, the cells arranged in rows radiating from the centre. 
The first type was the more frequent in the plants examined by the 
author. He supports the view of Bachmann and Borzi that these struc- 
tures are morphologically and physiologically of the nature of lenticels. 
Supernumerary Vascular Bundle in a Root.§ — Hr. E. Paratore calls 
attention to the occurrence of this rare phenomenon in a secondary root 
of Daphne melanoplithalmus. The bundle is intercalated between the 
elements of the secondary phloem, and was composed, in the example 
examined, of four dotted vessels, formed by the special activity of cambi- 
form cells of the secondary phloem, and directly from cambial cells. 
Anatomy of Chrysobalanese.|| — Dr. E. Kiister describes the minute 
anptomy of a number of genera and species of this order, with special 
reference to the deposition of silica. This deposition of silica is, as a 
rule, strictly localised. In the greater number of genera the cell- walls 
are strongly silicified, and there are in addition minute granules of silica 
deposited within the cell. These occur in the leaves, especially in the 
neighbourhood of the veins, and in the axis. Other points of structure 
are also treated of in detail. 
In another paper ^ the author gives further particulars of the charac- 
* Jahrb. f. wiss. Bot. (Pfeifer u. Strasburger), xxx. (1897) pp. 11(3-51. 
t Nuov. Giorn. Bot. Ital., iv. (1897) pp. 224-43. 
J Cf. this Journal, 1881, p. 74. § Malpighia, xi. (1897) pp. 82-4. 
I! Bot. Centralbl., Ixix. (1897) pp. 46-54, 98-106, 129-39, 161-9, 193-202,225-34 
(1 pb)* * Ber. Deutsch. Bot. Gesell., xv. (1897) pp. 134 8. 
