ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
501 
of plants that flourished in all parts of the world during the Devonian 
and Carboniferous periods, but disappeared at the close of the Permian, 
and has no nearer relative in our living flora than Equisetum. Of 
the ill-defined genus Asterophyllites , probably some species belong to 
Sphenophyllum, others to Catamites. 
Muscinese. 
Influence of the hygrometric state of the air on the position and 
function of the leaves of Mosses.* — M. E. Bastit points out that when 
such a moss as Polytrichum grows in moist places, the leaves are expanded 
and the upper convex surface is at a considerable angle with the stem ; 
while in dry situations the leaves are closed on themselves and on the 
stem. He found by experiment that, in accordance with the general 
law, respiration is considerably diminished, and the chlorophyll-function 
still more so, in the closed as compared to the expanded position. It 
is in winter, when the atmosphere is most saturated with moisture, that 
mosses elaborate with the greatest intensity their nutritive principles, 
owing to the expanded position of the leaves ; and this accounts for the 
formation of the oosphere and the sporogone at that period of the year. 
Sexual Organs and Impregnation in Xtiella.f — Dr. 0. Kruch has 
followed out the development of the archegones and antherids in Piella 
Clausonis. The young cellular tissue was treated with eau de Javelle, 
washed with abundance of distilled water, and stained with congo-red. 
For the study of the archegones in the process of development, the best 
results were obtained with methyl-green, after clarifying with oil of 
marjoram. In the formation of the antherids a marginal cell divides by 
a transverse septum into two portions, the lower of which forms the foot, 
and the upper one the body of the antherid. In the formation of the 
antherozoids the process of nuclear division corresponds, in all essential 
respects, with that observed by Strasburger in the case of flowering 
plants. The number of nuclear filaments in the successive divisions of 
the mother-cells of the antherozoids is invariably eight ; and during the 
process of impregnation the nucleus of the oosphere displays the same 
number of filaments. When the antherozoid penetrates the cytoplasm 
of the oosphere, it increases considerably in volume, and gives birth to 
the male nucleus, in which there are also evidently eight filaments ; the 
two sexual nuclei possess therefore the same number of filaments, and 
nearly the same dimensions. The secondary nuclei proceeding from the 
division of the nucleus of the embryo-cell present sixteen filaments. 
Characese. 
Growth of the Cell-wall in Chara fcetida.j: — Herr E. Zacharias 
found that the thickenings of the cell- wall of the rhizoids of Chara 
foetida are not caused by the excision of the node, nor by any nnchanical 
irritation of the rhizoid, but are formed whenever the plant is placed in 
pure water not previously containing any Chara , or in solution of sugar 
or dilute glycerin. It is probable that the rhizoids grow by apical 
growth. 
* Comptes Rendus, cxii. (1891) pp. 314-7. 
t Malpighia, iv. (1891) pp. 403-23 (2 pis.). 
t Ber. Deutsch. Bot. Gesell., viii. (1890) Gen.-Vers.-Heft, pp. 56-9. 
