194 
SUMMARY OF CURRENT RESEARCHES RELATING- TO 
Erythrism of Flowers.* — By the term eryihrism , Dr. X. Gillot pro- 
poses to designate the converse of albinism, the occurrence of a red 
tint in flowers ordinarily white. Familiar examples of this phenomenon 
are presented by Spirsea Ulmaria and many other species of Rosacete, 
Achillsea Millefolium , Beilis perennis, a considerable number of Umbel- 
liferse, &c. According to the writer it is promoted by an abnormally 
high temperature or an unusual degree of light. 
Arctic and Alpine Plants.f — M. G. Bonnier compares the structure 
of the same plant growing in Arctic and in Alpine regions in the case of 
a number of species belonging to Spitzbergen or Jan Mayen Land on the 
one hand, and to the Alps or Pyrenees on the other hand. He finds, in 
all the species examined, that the arctic plant exhibits the following 
characters, more or less strongly accentuated, as compared with the 
same species from alpine localities. The lignified elements are reduced 
in number, their walls are thinner, and the diameter of the vessels is 
smaller. The leaves are thicker but less differentiated ; the palisade 
tissue is much less strongly developed, the lacunae or intercellular spaces 
much more so. The epiderm of the leaves and stem is less coherent, 
and its cuticle thinner. All the tissues of the leaf, stem, and root 
exhibit a greater or less tendency to a rounding of the cells, which often 
form trabecules separating large intercellular spaces filled with air. 
These differences are attributed by the author mainly to different con- 
ditions as to the moisture of the air and to light. In arctic regions the 
air is more charged with moisture, and the light is more continuous but 
less intense, than in alpine regions. 
Ombrophilous and Ombrophobous Vegetation.^ — Prof. J. Wiesner 
calls attention to the character of the foliage displayed both in temperate 
(Austria) and in tropical (Java) climates, by plants which, on the one 
hand are uninjured ( ombrophilous ), and on the other hand are injured 
( ombrophobous ) by excessive rainfall. These characters do not necessarily 
go with an adaptation for a moist or a dry soil. Some species — e. g. 
Impatiens noli-tangere , Prenanthes purpurea — growing in moist shady 
situations, are nevertheless ombrophobous. Xerophilous plants, on the 
other hand, are hardly ever ombrophilous. As a rule, the power of 
resistance to rain increases with the growth of the leaf, reaches a 
maximum, and then again diminishes. Leaves the upper surface of 
which can be moistened are usually ombrophilous, those in which the 
upper surface is covered by a coating of wax ombrophobous. The pro- 
tection of ombrophilous leaves against the injurious action of excessive 
rain appears to be afforded by the presence of antiseptic substances. 
In tropical forests it is common for the peripheral leaves to assume a 
vertical position, so as to be but little affected by the rain, while the 
central leaves retain a normal horizontal position. When young no 
large formation of chlorophyll takes place in the leaves. The sensitive 
folding up of the leaves of Mimosa under concussion is a protection 
against the injurious effects of excessive rainfall. 
* Bull. Soc. Bot. France, xl. 1893 (1894). Sess. Extraord., pp. clxxxix-cxciv. 
t Kev. Ge'n. de Bot. (Bonnier) vi. (1894) pp. 505-27 (4 pis.). 
% SB. K. Akad. Wiss. Wien, cii. (1893) pp. 503-21, ciii. (1894) pp. 169-91. Cf. 
this Journal, 1894, p. 82. 
