ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
297 
B. Physiology. 
(1) Reproduction, and Embryology. 
Embryo-sac of Gamopetalae.* — Dr. G. Bolicka-Iwanowska has 
studied the formation and development of the embryo-sac in certain 
genera belonging to the orders Scrophulariaceae, Gesneraceae, Pedalineae, 
Plantaginaceae, and Dipsacaceae. The following are some of the general 
conclusions arrived at. 
The presence of a haustorium and the thickness of the integuments 
are in close relationship to one another ; but the presence of a haus- 
torium cannot in itself be considered a sound basis for classification. 
A haustorial apparatus occurs in the Scrophulariaceae (Antirrhineae and 
Rhinantheae), Utriculariaceae, Pedalineae, and Plantaginaceae, and in 
Campanula rotundifolia and Lobelia inflata among Campanulaceae. The 
haustorium having always for its purpose the conduction of nutrient 
substances, it has usually a direct connection with a special nutritive 
tissue, and the haustorium is then located near the chalaza ; when it 
is situated near the micropyle, there is often no special nutrient tissue. 
In the genera where there is a chalazian haustorium, there is no true 
fibrovascular bundle in the integument, though there may be in the 
placenta. 
The author attributes to the nucleus an important nutritive function. 
The cells of the haustorium are not generally invested with a mem- 
brane; and when one is formed it rapidly becomes gelified. The 
tapetal cells do not appear to play any part in the protection of the 
embryo-sac ; they probably form a ferment and serve a digestive func- 
tion ; for they are often very persistent. The synergids have no 
permanent nutritive function ; they always disappear after impregna- 
tion. In the genera studied, the antipodals, when present, have only a 
temporary function. 
Embryo-sac of Compositse.f — Mile. M. Goldflus has studied this 
subject in a number of genera and species, especially in relation to the 
structure and functions of the epithelial layer and the antipodals. As 
a general conclusion, she states that the embryo-sac of Compositae is 
surrounded by the inner layer of the integument of the ovule differen- 
tiated into digestive cells. The antipodals are usually arranged in a 
row which penetrates, like a haustorium, into the axial portion of the 
ovule. The antipodals are generally connected with a string of con- 
ducting cells pointing towards the extremity of the raphial bundle, and 
appear to furnish a connecting link between the embryo-sac and the 
elaborated digestible substances in the ovule. But the number and 
arrangement of the antipodals differ greatly in the different genera. 
The integument is at an early period differentiated into an outer 
and an inner portion ; the latter, surrounding the base and sides of the 
embryo-sac, has frequently been confounded with the nucellus, and has 
a distinct nutritive function. As a rule, there is no epithelial layer 
between this portion of the integument and the ovules. The antipodals 
and epithelial cells of Compositae are less erythrophilous than the sexual 
* Flora, lxxxvi. (1899) pp. 47-71 (8 pis.). 
t Jouru. de Bot. (Morot), xii. (1898) pp. 374-84 ; xiii. (1899) pp. 9-17, 49-59, 
87-96 (6 pis. and 18 figs.). 
1899 
X 
