ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 225 
its fullest development in G. Gnemon ; in G. Rumphianum it could not 
bo detected. 
In the perfect female flowers there arc always at first numerous 
embryo-sacs. In G. verrucosum sp. n., ovalifolium sp. n., and Rumphianum, 
these are finally reduced to one ; in G. Gnemon and funicularc there arc 
often still two or three at the period of fertilization, all capable of 
impregnation. While the pollen -grains are still within the anther they 
contain three nuclei, one of which becomes subsequently absorbed. 
Within the pollen-tube the generative nucleus (in G. funicular e) divides, 
as in Coniferte, though it is doubtful whether two distinct generative 
cells are formed. The two generative nuclei appear to enter the 
embryo-sac, and to coalesce with one of its nuclei. The staining re- 
actions of the sexual nuclei do not correspond with the observations of 
Rosen and Schottlander. The author’s previous statements with regard 
to the changes which take place in the generative nucleus before im- 
pregnation must be modified. After impregnation, either the primary 
germ-nuclei divide, become enclosed in the endosperm, and develope 
into long tubular embryos, or they become enclosed in one of the 
endosperm-cells, and produce, by division, the secondary true embryo- 
cells which subsequently develope into pro-embryos. 
Herr Karsten establishes six species of Gnetum , two of them new. 
Embryology of Veronica hederaefolia.* — According to Dr. L. 
Buscalioni the ovule of this plant is of the monochlamydeous type, 
consisting of a very small nucellus, and of an integument formed 
from the epiderm of the ovular tubercle. The hypodermal cell of 
the ovular tubercle divides into four cells, one only of which developes, 
and becomes the embryo-sac. The endosperm is formed only in the 
central part of the embryo-sac, the two ends growing into appen- 
dages which the author calls the chalazal and the micropylar arms. The 
originally anatropous ovule thus assumes a somewhat campylotropous 
appearance. The raphe has no xylem-vessels nor sieve-tubes. The endo- 
sperm divides into a central and a peripheral portion, the cells of the 
latter being in protoplasmic communication with one another. A little 
before the seed is ripe, a cushion of endosperm is formed round it, which 
brings the two arms together on the concave side of the seed, and gives 
it a shell-like form. The suspensor forces itself into the micropylar 
arm of the embryo-sac, and consists of a long row of cells full of starch. 
It serves to supply food-material to the ovule, and, at a later period, 
becomes entirely absorbed. The epiderm, and partially also the sub- 
jacent layers of the integument of the ovule, become converted before 
maturity into a spongy mass, the innermost layer alone forming the testa 
of the ripe seed. The membranes of both ends of the embryo-sac, and 
those of the cells of the chalazal branch of the endosperm, increase in 
thickness by the apposition of granules of cellulose produced from the 
microsomes of the protoplasm. 
Cross-Pollination and Self-Pollination. — Mr. C. Robertson f describes 
the adaptation of the flower for cross-pollination in a number of 
* Mem. R. Accad. Sci. Torino, xliii. (1893) pp. 477-522 (2 pis.). 
t Trans. Acad. Sci. St. Louis, vi. (1893) pp. 101-31. Cf. this Journal, 1893, 
p. 503. 
