ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
481 
flap an outgrowth in a radial plane, somewhat similar to that of the 
leaf of Iris or the phyllode of Acacia. There is no evidence here of 
coalescence of pinnae. 
Modifications of Leaves in Maritime Plants.* * * § — M. P. Lesage draws 
the following conclusions as the result of his investigations on this 
subject : — (1) Plants living near the sea have thicker leaves than those 
inland ; but there are certain exceptions to this rule. (2) The palisade- 
cells are generally much developed and the lacunae reduced in maritime 
plants. (3) Chlorophyll is generally less abundant in the cells of plants 
living near the sea. This conclusion is not quite so constant as the 
preceding. (4) The fleshiness of leaves, the development of the palisade 
cells, the reduction of the lacunae, and the diminution of the chloro- 
phyll, can be effected by experimental cultures where salt is the variable 
element. 
Structure of the Margin of Leaves.f — Herr R. Hintz describes in 
great detail the various modes in which the leaves of plants are 
mechanically protected against tearing, whether by local mechanical 
thickening, or by the special arrangement of the marginal veins. These 
he classifies under three types, and the connection between these special 
structures and the arrangements for storing up water in the margins of 
the leaves are further detailed. 
Fall of Hairs4 — Herr W. Karner describes the conditions favour- 
able to the formation of hairs on leaves and other parts of plants, and 
the causes which lead to their subsequent disappearance. This latter 
may result from the amount of water in the cells, from changes of 
temperature or moisture in the air, from the formation of a coating 
of silica on the surface, from rain, wind, and other causes. The amount of 
water in the cell-wall also influences the durability, as well as the stiff- 
ness or brittleness of the hairs. The mechanical arrangements by which 
the hairs are detached are also described. 
B. Physiology. 
(1) Reproduction and Germination. 
Pollination and Distribution of the Sexual Organs.§— Herr A. 
Schulz continues his researches on this subject, recording a very large 
number of observations on plants belonging to a great variety of natural 
orders. A few general remarks are appended. 
In the family Silenem of Caryophyllaceae, the proterandry is in many 
species so marked as to render self-fertilization impossible. Only two 
observed species, Tunica prolifera and Vaccaria parviflora, were homo- 
gamous. In the family Alsineae, on the other hand, the proterandry is 
* Rev. Gen. de Bot. (Bonnier), ii. (1890) pp. 55-65, 106-21, 163-75 (3 pis. and 
1 fig.). Cf. this Journal, ante , p. 363. 
f Nova Acta K. Leop.-Carol. Akad. Naturf., liv. (1889) pp. 97-214 (3 pis.). 
See Bot. Centralbl., xlii. (1890) p. 50. 
t Nova Acta K. Leop.-Carol. Akad. Naturf., liv. See Bot. Centralbl., xli. (1890) 
p. 294. 
§ Biblioth. Botan. (Luerssen u. Haenlein), Heft 17, 224 pp., 1890. Cf. this 
Journal, 1888, p. 612. 
