ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 313 



recalls GuignarcTs observation on the tulip, and Campbell's reference to 

 secreting cells in the funicle of Najas. This secretion probably serves 

 as a medium through which the substance capable of attracting pollen- 

 tubes diffuses outward from the micropyle. The egg-cell is fertilised 

 shortly after the formation of the secretion, after which there is no 

 further secretion. 



Embryogeny of Ficus hirta.* — M. Treub describes the pollination 

 of the female flowers of Ficus hirta by the gall-insect. The winged 

 females carry pollen into the female receptacle after forcing the narrow 

 entrance and often losing wings or antennas in the passage. In their 

 efforts to pierce the summit of the female flower in order to deposit their 

 eggs therein, they carry pollen to the stigma. Treub carefully studied 

 the development of the ovule and finds two integuments and a normal 

 embryo-sac ; but an examination of more than two thousand sections 

 failed to show more than the beginning of germination of the pollen ; 

 the tube was never found in the deeper part of the stigmas, and there 

 was no indication of fertilisation of the egg. As a normal embryo 

 develops from the egg, the author concludes that it is produced 

 parthenogenetically. The ovule shows two anatomical peculiarities, 

 which, while increasing the difficulty of fertilisation, render partheno- 

 genesis very probable. The micropyle is obliterated by fusion of the 

 edges of the internal integument, and the epidermis of the nucellus 

 becomes strongly thickened, forming a compact cap above the embryo- 

 sac. The secondary nucleus of the embryo-sac on division shows only 

 a distant resemblance to karyokinetic stages, dividing with great rapidity 

 by reduced or abridged mitosis. This is explained by the absence of the 

 stimulus of the fusion of the male nucleus. This anomaly affords an 

 indirect proof of the parthenogenetic origin of the embryo. We must 

 regard the puncture by the insect as a special stimulus to partheno- 

 genesis. 



Chalazogamy in Carya olivseformis.t— F. H. Billings finds the 

 course of the pollen-tube in this species to resemble that described by 

 Nawaschin in the walnut. The general morphological character of the 

 ovary-wall and ovule resembles that described for Juglans by the Russian 

 observer. The placenta nearly fills the lower part of the ovary-cavity, 

 forming the tissue through which the pollen-tube travels to the base of the 

 ovule. The pollen-tube passes down the conducting tissue of the style, 

 till near the ovary-cavity, where it turns and passes down the ovary-wall 

 close to the margin of the cavity. The tissue through which it travels 

 consists of isodiametric cells, and does not in any way suggest a con- 

 ducting tissue. At a point a little below the funicle the tube curves, 

 passes through a region of deeply staining cells (as though mucilaginous), 

 and turns upwards towards the embryo-sac. The tube seems to branch 

 as was described in Juglans. A micropylar canal is present, but no 

 pollen-tubes were found entering it. 



Biology of Fruit in Malvaceae.:}: — B. P. G. Hochreutincr describes 

 the extreme variability of the fruit in Malvaceae, and of the mechanism 



* Biblioth. Univers. Arch. So'. Phys. et Nat. (Geneva), se'r. 4, xiv. (1902) 

 pp. 496-8. t Bot. Ga-: , xxxv. (1903) pp. 134-5 (fig. in text). 



+ Biblioth. Univers. Arch. f?c:. J'hys. ct Nat., torn, cit., pp. 510-7. 



