ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
350 
giferous filaments of Phycomyces to hydrotropism. He defines hydro- 
tropism, whether positive or negative, as the bending of an organ 
towards the point, not where it will find a maximum or minimum of 
moisture, but where it will, within certain limits, transpire most or least. 
(4) Chemical Chang-es (including- Respiration and Fermentation). 
Formation of Calcium oxalate.* * * § — According to Herr H. K. Muller 
the crystals of calcium oxalate which are found imbedded in the cell- 
wall of plants are either formed in the membrane itself without contact 
with the cell-contents, or in the interior of the cell, and are subsequently 
enclosed in the cell-wall. The former is much the more frequent mode. 
Herr H. Warlich f finds a steady increase in the amount of calcium 
oxalate in leaves during their growth, and even after this has ceased. 
Under certain circumstances it is again absorbed by the plant. 
Influence of Phosphoric Acid on the Formation of Chlorophyll.*— 
According to experiments made by Herr 0. Loew, phosphoric acid is 
necessary for the full development of chlorophyll. Spirogyra majuscula 
was grown in a nutrient solution containing O’ 2 p. m. calcium nitrate 
and 0*2 p. m. ammonium sulphate. Elongation of the cells took place, 
but only to a small extent, and no cell-division ; the chlorophyll layer 
was pale and yellowish, and its movements sluggish. 0*02 p. m. 
ferrous sulphate was now added, and the culture divided into two 
portions ; 0 • 08 p. m. disodium phosphate was added to one portion, but 
not to the other. After five days no change was observed in the latter 
portion; while the former had become dark green, cell-division took 
place, and the movements of the chlorophyll became lively. 
B. CRYPTOGAMIA. 
Cryptogamia Vascularia. 
Hygrophilous Ferns.§ — Herr K. Giesenhagen points out the re- 
markable degree of variation in the structure of the frond of the tropical 
fern Asplenium obtusifolium, between the typical form and the variety 
aquaticum, according as the plant grows in dry or in moist localities. A 
new species Trichomanes Goebelianum is described, of which the rhizome, 
leaf-stalks, &c., are densely covered with root-hairs. 
Oophore-generation of the Hymenophyllace8e.|| — Prof. K. Goebel 
describes the prothallium of Trichomanes rigidum and sinuosum from 
South America. The former is entirely filiform ; the latter partly 
filiform, partly unilamellar. Both multiply by buds ; both are monoe- 
cious ; in both the archegones are elevated on archegoniophores. The 
filiform prothallium of T. rigidum probably indicates the simplest form 
of fern, and appears to be closely connected with such simple moss-forms 
* ‘Ueb. d. Entstehung v. Kalkoxalatkrystallen in pflanzlichen Membranen,’ 
Prag, 1890, 50 pp. and 1 pi. See Bot. Centraibl., liii. (1893) p. 111. 
f ‘ Ueb. Calciumoxalat in den Pflanzen,’ Marburg, 1892, 2 pp. and 1 pi. See 
Bot. Centraibl., liii. (1893) p. 113. 
X Ann. Agron., xviii. pp. 270-1. See Journ. Chem. Soc., 1892, Abstr., p. 1372. 
§ Flora, lxxvi. (1892) Erganzungsband, pp. 157-81 (3 figs.). 
U Tom. cit., pp. 101-16 (3 pis. and 1 fig.). 
