192 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
v. Hohnel to cortical pressure ; and gives reasons for believing that 
these displacements are not found in the living tissues, but are the result 
of the mode in which the preparations have been treated. The bast- 
fibres of different plants show a very different degree of sensitiveness to 
mechanical influences. 
Absorption of the Secondary Cell-membrane in Seeds.* — Dr. T. 
Elfert has studied the various modes in which the secondary cell- 
membrane of seeds is absorbed during germination. These consist in 
the occurrence of the following changes. Shallow hemispherical projec- 
tions and depressions make their appearance on the innermost boundary 
of the inner lamella. These projections and depressions become gradually 
deeper, until the thickened cell-wall assumes an irregular jagged form. 
The cell-wall then becomes absorbed as far as the central lamella, and 
a thin-walled parenchymatous tissue remains consisting of nothing but 
the central lamella. This absorption of the thickening masses is accom- 
panied by the appearance of starch-grains. The seeds examined may 
be divided into two classes, — those in which the thickened cell-walls 
do not, and those in which they do consist of reserve food-materials ; 
and this food-material may be composed either of cellulose or of 
amyloid. 
Structure and Formation of Stomates.f — Sig. F. Tognini has 
examined the mode of formation of the stomates in the cotyledons, 
foliage-leaves, petals, and stem of 34 species belonging to different 
orders of Dicotyledons, and asserts that the usual statement that this is 
uniform for the same species can only be accepted with great modifica- 
tion ; it may vary even in the same organ of the same plant ; the greatest 
variation is observable in the cotyledons. The immediate formation of 
the mother-cell of a stomate from a complete epidermal cell occurs in 
Eucalyptus globulus, Hypericum hircinum , Acer Pseudo-platanus , Vitis 
vinifera , Syringa persica , and Apocynum cannabinum. In Lactuca virosa 
the mother-cell is produced by four successive divisions in four different 
directions. From the facts above stated it follows that the mode of 
formation of the stomates cannot be used as a systematic character in 
plants. The cotyledons of the Phaseoleac are not always destitute of 
stomates, as has been stated. As a general rule the mode of formation 
of the first stomates of an organ is much more simple than that of the 
later ones. 
Wood of the Magnoliacese.f — Dr. R. Groppler has examined the 
structure of the wood in a large number of species of Magnoliacese. He 
finds an intermediate stage between the simple structure of Hrimys, 
IlUcium, &c., and the complicated one of Magnolia and Liriodendron, in 
several genera, of which Michelia may be taken as a type. The varia- 
tions in the structure of the wood correspond, in general terms, to the 
accepted classification into suborders. In all the species a scalariform 
marking occurs in the vessels, which passes over into bordered pits. 
Spiral thickening was seen only very rarely. Libriform is almost 
* Biblioth. Bot. (Luerssen and Frank) Heft 30, 1804 (23 pp. and 2 pis.). 
t Atti R. 1st. Bot. R. Univ. Pavia, iv., 42 pp. and 3 pis. See Bot. Centralbl., 1894, 
Beih., p. 423. 
% Biblioth. Bot. (Luerssen and Frank) Heft 31, 1894 (51 pp. and 4 pis.). 
