592 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
known in Avicennia officinalis , wliere tlie endosperm and embryo project 
through the micropyle into the ovary, with the exception of certain cells 
which increase enormously in size, and constitute a liaustorium which 
conveys food-material to the endosperm and embryo. 
In Brugaiera eriopetala a secondary endosperm-tissue is formed, from 
which one-celled or many-celled appendages penetrate into the loose 
tissue of the integument. Saccate prolongations are then put out from 
certain of the endosperm-cells, which penetrate into the tissue of the 
cotyledons, and serve to convey food-materials to the seedling. Both 
the outermost layer of cells of the cotyledons and the tissue of the 
endosperm give out a ferment which rapidly corrodes starch. A portion 
of the endosperm which projects through the micropyle sends out strong 
haustoria into the calyx- tube. The hypocotyl of this tree has very 
peculiar stomates, in which the guard-cells are not motile, and the 
cavity is divided into two chambers. 
In ffliizophora mucronata the seedlings may attain the height of a 
metre while still attached to the mother-plant. The upper part of the 
cotyledons is here provided with a number of papillae which excrete a 
starch -destroying enzyme. In AEgiceras majus prolongations which 
have the properties of haustoria are also put out by the endosperm. 
Production of Oxygen and Chlorophyll. * — Herr Th. W. Engel- 
mann shows, by means of excellent coloured illustrations, the phenomena 
attending the excretion of oxygen by chromophyllaceous cells under the 
influence of light. The method of experiment is simple, and consists in 
watching the aggregation of mobile aerobic bacteria when placed in a 
drop of water in which is a vegetable cell containing chromophyll of 
any colour. The illustrations show excellently well how the bacteria 
crowd around the chromophyll when it is exposed to light. 
Fixation of Free Nitrogen by Algae. | — Herr P. Kossowitsch con- 
firms the statement of Frank, Schloesing, and Laurent that certain alga) 
have the property of fixing the free nitrogen of the atmosphere. It is, 
however, uncertain whether this is due to the algae themselves, or to the 
bacteria which find a favourable nidus in their mucilaginous envelope. 
With some algae, e. g. Cystococcus , Stichococcus , and Microcoleus vaginatus 
(according to Schloesing and Laurent), it is certain that this property is 
not present. A convenient apparatus for the pure culture of algae is 
described. 
Absorption of Water by the Green Parts of Plants.J — As the re- 
sults of a series of experiments performed on a number of different 
plants, Mr. W. F. Ganong concludes that the absorption of water 
through the green parts is, in all probability, not a general phenomenon 
with ordinary land plants, or at all events does not take place to an 
appreciable amount ; though with plants of special habit and special 
structure, such as the epiphytic Bromeliacese, it is quite possible that it 
does occur. 
* Yerhandl. K. Akad. Wetenschappen Amsterdam (Tweede Sectie), Deel iii. 
No. 11 (1 pi.). 
f Bot. Ztg., Iii. (1894) l te Abtheil., pp. 97-116 (2 figs.). Cf. this Journal, ante , 
p. 86. % Bot. Gazette, xix. (1894) pp. 136-43. 
