ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
65 
spond to the eight male reproductive cells which develope from one pol- 
len-mother-cell. The primary endosperm-cell must be regarded as a 
true embryo resulting from the union of two sexual cells, but destined 
as a storehouse of food-material for the impregnated oosphere. 
The structure of the nucleus and nucleoles of the oosphere is 
described in detail, and the stages in the formation of the endosperm 
cell, including the amoeboid movements of the cell-plasms of the two 
primordial cells, which lead to their conjugation. The directing spheres 
or tinoleucites play only an indirect part in the actual process of im- 
pregnation. 
The concluding portion of the paper is occupied by a discussion of 
the various theories of fertilization, and by a comparison of the pheno- 
mena in the animal and vegetable kingdoms. 
Sexual Organs of Flowers.* — Herr A. Schulz publishes a number of 
observations on the flowers of plants usually regarded as unisexual. In 
Alnus glutinosa hermaphrodite flowers or transitional forms are to be 
found at the base of all the male catkins. Hermaphrodite flowers also 
occur in the birch, though less frequently ; very rarely in the hazel ; 
in the oak there are frequently ovaries at the base of the male catkins, 
and rudiments of stamens in the female flowers. In the ash we have all 
kinds of condition — male, female, and hermaphrodite flowers, and 
monoecious, dioecious, and polygamous individuals. This tree is pro- 
bably on the road to becoming completely dioecious. 
Hybridization of the Vine.t— M. A. Millardet gives detailed prac- 
tical instructions for the hybridization of the vine and the culture of 
the hybrids, preceded by some general remarks. The so-called hybrid 
vines which are cultivated in Europe are not true hybrids, i. e. results 
of the crossing of distinct species, but spring from the crossing of 
different races of the same species, Vitis vinifera. 
In the native state, both V. vinifera and other species of the genus 
have two kinds of flower, hermaphrodite and male, the female organ 
being subject to all degrees of abortion in the latter. There is a re- 
markable difference in the stamens of the two kinds of flower : in the 
former the filaments are short and curved backwards, so as to remove 
the anther as far as possible from the stigma ; in the latter they are long 
and erect. In the cultivated varieties, however, all of which have only 
hermaphrodite flowers, the filaments are long and erect, as in the male 
flowers of the wild plant. The pollen-grains from the short curved 
stamens will not germinate in a solution of sugar ; but the author states 
that they will germinate on the stigma. In the wild state the vine is 
anemophilous, though the flowers have a powerful odour, the purpose of 
which is obscure. In the cultivated state two small Coleoptera, Dasytes 
griseus and Scraptia fusca , were observed abundantly on the flowers, 
and they may also probably take some part in the pollination. The 
author states that it is beyond question that in the vine it is the male 
parent that exercises the preponderating influence on the hybrid. 
Mr. S. A. Beach J enumerates eight American species of vine, and 
their hybrids and crosses, in which he has observed self-pollination. 
* Ber. Deutsch. Bot. Gesell., x. (1892) pp. 303-13, 395-409. 
t Mem. Soc. Sci. Phys. et Nat. Bordeaux, ii. (1891) pp. 301-38 (6 figs.). 
t Bot. Gazette, xvii. (1892) p. 282. 
1893. 
F 
