ZOOLOGY AND BOTANY, MICRO 3COPY, ETC. 
407 
Tubers of Aconitum.* — Dr. C. Hartwich describes several different 
kinds of abnormality in the tubers of species of Aconitum , natives of 
Switzerland, and derives from them conclusions as to the genetic relation- 
ship of the species. They comprise irregularities as to the disposition 
of the cambium and of the elements of the vascular bundles, and in the 
occurrence of a layer of cells in the cortex distinguished from the rest 
of this tissue by a difference in their refractive power. 
Replacement of the Primary Root by a Secondary Root.| — Accor- 
ding to M. Boirivaut, it very frequently happens when the primary root 
of a Dicotyledon is destroyed, that a secondary root takes its place, and 
this secondary root then assumes very much the structure of the primary 
root. This is especially manifested in an increase in the number of 
vascular bundles. 
Spinous Roots 4 — Dr. D. H. Scott records two instances of this un- 
usual structure, — in Dioscorea prehensilis, and in Morseci sp. belong- 
ing to the Irideae. In the former case these spinous roots are produced 
entirely underground ; in the latter they spring from the swollen base 
of the stem. In both cases they resemble true roots in their anatomical 
structure. 
Structure of Bromeliaceae.§ — The late Dr. F. Muller records his 
observations on several species of this order, natives of Brazil. The 
honey-glands of Vriesia are described, situated on the septa of the ovary. 
In many species of Tillandsieae the author finds bracteoles ( Vorblatter'), 
the existence of which has not been detected by previous observers. 
Morphology of Thelygonum Cynocrambe.jj — Of this remarkable 
plant of the Mediterranean flora, of uncertain affinities, placed by Lindley 
among the Chenopodiaceae, Dr. G. Balicka-Iwanowska has made a detailed 
examination, of which the following are the more important results. The 
stem is monopodial. The male flowers have no rudiments of bracts or 
supporting leaves, while the female flowers have both. The ovules, 
which are at first horizontal and anatropous, assume later a horseshoe 
shape. A large amount of mucilage is present in the colleters and in a 
circular swelling of the leaf-stalk. 
£. Physiology. 
Cl) Reproduction and Embryology. 
Moebius on Reproduction .t — Prof. M. Moebius has brought together 
in one volume all his previous observations on the various modes of 
reproduction in the vegetable kingdom, and has added some new obser- 
vations and theories. 
Instead of the primary classification of modes of reproduction into 
sexual and non-sexual, he proposes one into reproduction by buds and 
by germs ; the distinction lying in the rejuvenescence of the cell or cells 
in the case [of germs, while no such rejuvenescence takes place in the 
* Bot. Centralbl., lxx. (1897) pp. 114-20, 14G-52, 178-84 (2 pis.). 
f Coraptes Rendus, exxv. (1897) pp. 136-8. 
+ Ann. of Bot., xi. (1897) pp. 327-32 (2 pis.). 
§ Flora, Ixxxiii. (1897) pp. 454-86 (2 pis.). 
|| Tom. cit., pp. 357-66 (10 figs.). 
% ‘ Beilr. z. Lehre v. d. Fortpflanzung d. Gewachse,’ Jena, 1897, vi. and 212 pp. 
and 36 figs. 
