436 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
for a long period after impregnation ; one of them is apparently 
occasionally fertilised. The antipodals are seated at the opposite end 
of the embryo-sac. The suspensor remains unicellular until after the 
first divisions have made their appearance in the embryo. The nuclei 
of the endosperm divide pari passu with those of the embryo, until a 
body of 32 cells is formed, each with its own nucleus. This is subse- 
quently almost entirely resorbed, until only two layers of strongly com- 
pressed endosperm-cells remain, which assume the function of an inner 
integument to the seed. 
Embryo-Sac of Alisma.* — Mr. J. H. Schaffner has investigated the 
development of the embryo-sac of Alisma Plantago, and gives the 
following as his more important conclusions. During the conjugation 
of the two polar nuclei the four centrospheres conjugate in couples, 
resulting in the formation of two new ones for the definitive nucleus. 
The endosperm results entirely from the division of the definitive 
nucleus. The division of the generative nucleus of the pollen-grain 
occurs within the grain. Both of the pollen-nuclei enter, with the pollen- 
tube, into the embryo-sac, but only the lower takes part in the act of 
fertilisation, the other remaining in the tube. The nucleus of one 
of the synergids is entirely absorbed when in contact with the pollen- 
tube ; the other is also dissolved later. The centrospheres of the lower 
pollen-nucleus precede it as it approaches the oosphere. The nucleus 
of the oosphere becomes bulged out on the side nearest the pollen- 
nucleus, and its centrospheres, being situated immediately opposite 
the bulge, travel slightly towards the approaching pollen-nucleus. All 
the stages preliminary to the conjugation of the male and female nuclei 
indicate a conjugation of their centrospheres at the time of impregna- 
tion of the oosphere. 
Ovules of Angiosperms.f — Herr M. Westermaier describes a number 
of special cases of the development of the antipodal apparatus in the 
embryo-sac. In Forsythia sp. there is at the antipodal end of the sac 
a cylindrical cellular structure which he terms the “ antipodal cell- 
body,” which is present in young ovules, the embryo-sac above this body 
appearing to collapse. The funicle contains no vascular bundle ; one 
is, however, present in Syringa, some species of which possess also a 
similar antipodal cell-body. In Alstrcemeria, the antipodal apparatus 
has assumed a lateral position from the unequal growth of the embryo- 
sac. In the CruciferaB and Resedaceae there is no true antipodal appara- 
tus ; but it is probable that at the basal region of the embryo-sac there 
are special contrivances for the nutrition of the embryo. 
The anatropy of ovules is the result, according to the author, not of 
any cohesion in growth, but of the mode of growth of the funicle and 
its relation to the integument. From a theoretical point of view, the 
funicle is homologous with the pedicel of the sporange. 
In another paper t the author corrects seme errors into which he has 
fallen with regard to the ovule of the Oleaceae and of Anemone. 
* Bot. Gazette, xxi. (1896) pp. 123-32 (2 pis.). 
+ Beitr. z. wiss. Bot. (Funfstiick), i. (1895) pp. 255-80 (2 pis.). See Bot. Ceu- 
tralbl., lxvi. (1896) p. 128. 
X Ber. Deutscb. Bot. Gesell., xiv. (1896) pp. 33-5. 
