ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
757 
The wall of the anther is composed of four distinct layers — the 
epidermal layer or exothecium, the endothecium or fibrous layer, the 
temporary layer of Strasburger, and the tapetal layer. The cells of this 
last layer are especially rich in protoplasm, and their nuclei are very 
strongly coloured by pigments. There are two nuclei in each cell, but 
these often unite into an hour-glass-shaped single nucleus. A vascular 
bundle runs through the connective, surrounded by large parenchymatous 
cells. The primary pollen-mother-cells are much larger than those of 
the surrounding layers, and are at first polygonal in form ; their nuclei 
have only eight chromatin-segments. 
The embryo-sac is characterized throughout the order, with a few 
exceptions, by the large number of antipodals, which fill up, at a late 
period, the greater part of the embryo-sac. The nuclei frequently 
divide without the formation of walls. The number of chromatin- 
granules is twelve in the earlier, twenty-four in the later stages. Each 
nucleus has one, less often two or three, nucleoles. The author adopts 
the view that the antipodals exercise an important function in the con- 
veyance of nutrient materials to the embryo. 
Fertilization of the Fig.* — As the result of observations made in 
San Francisco by Herr G. Eisen, Graf zu Solms-Laubach believes that 
the true Smyrna fig is at present unknown in Europe, and that the cul- 
tivated figs are of two different classes, viz. — (1) the Smyrna fig, which 
requires pollination or caprification in order to produce fruit ; and (2) the 
ordinary edible fig, which can produce the fruit (receptacle), but with- 
out seeds, even when not artificially pollinated. The ancestor of the 
Smyrna fig appears to be the female Ficus Caprificus , while the Italian 
fig is derived from the male plant. 
Pollination of Rohdea.f — Sig. S. Baroni has studied the mode of 
pollination of Pohdea japonica , and finds it to be due chiefly to gastro- 
podous Mollusca, though insects (especially ants) and worms take some 
part in it. The anatomy of the plant is described in detail, and it is 
stated that in the tissue of the anther are two layers only of fibrous cells, 
and that one of the two integuments which invest the ovule is absorbed 
in the ripe seed. The genus is placed in the tribe Asparageae of 
Liliaceae. 
Parasitic Castration of Knautia arvensis.J — M. Molliard has ex- 
amined plants of Knautia arvensis attacked by Peronospora violacea, in 
which the effect has been to cause the central flowers of the inflorescence 
to assume the appearance of the ray-flowers ; they are much larger in size, 
with a deeply lobed irregular corolla, and of a deeper hue ; both male 
and female organs were also more or less completely atrophied. In 
other plants, attacked by Ustilago Scabiosse, the anthers and many of the 
ovaries were also atrophied, while others of the ovaries were fertile, and 
two or three times the normal size. 
* Bot. Ztg., li. (1893) lte Abtheil., pp. 81-4. 
f Nuov. Giorn. Bot. Ital., xxv. (1893) pp. 152-75. 
X Comptes Rendus, cxvi. (1893) pp. 1306-8. 
