218 BOTANICAL GAZETTE [MARCH 
results of experimental cultures, directions for raising various crops with appro- 
priate fertilizers, business maxims, a plea for good roads, etc. It has neither 
coherence nor apparent object beyond advertising under the guise of a hand- 
book.—C. R. B. 
Botanical literature.—Section M of the International Catalogue of Scientific 
Literature, devoted to botany, was published in July by the Royal Society of 
ondon. It contains the literature for 1904, and some belated entries for the 
preceding three years.29 The volumes are improving in cit ears and 
accuracy. Certainly no research laboratory can do without them.— a 
Volatile oils.—The semi-annual report of Scuimmet & Co., dated October- 
November 1906, contains an unusually extensive statement of the trade conditions 
respecting the volatile oils and the plants which produce them. Fifty pages also 
are devoted to a summary of recent researches on terpenes and the terpene 
derivatives.*°—C. R. B. 
Genera Siphonogamarum.—The ninth fascicle of Datta TorRE and HARMs"* 
list of the genera of seed plants continues the general alphabetical index of names, 
the last entry being Diplopeltis.——J. M. C 
NOTES FOR STUDENTS 
Galvanotropism of roots.—T wo studies on this topic appeared almost simul- 
taneously last autumn. SCHELLENBERG investigated the influence of salts on 
the direction of growth of the roots of peas,'? using roots of seedlings grown to a 
length of 3-4°™ in moist sawdust and then fixed vertical in very dilute solutions 
of various salts, with cotyledons exposed. The experimental vessel with the 
solution was connected by filter-paper bridges with vessels at each side which 
contained the same solution, and into these were led metallic electrodes with a 
current of 2-6 volts, and 0.1 to .oor milliampere. Neglecting the effects of 
stronger currents, which produce curvatures due to death or disturbances of 
growth, the vast preponderance of response was a turning toward the anode, 
NH,Cl alone showing 6 out of 8 curvatures toward the cathode. Chemotropic 
studies have shown that the reaction changes with concentration; it likewise 
9 International Catalogue of. Scientific Literature. Fourth annual issue. M. 
il bran for < International Council by the Royal Society of London. 
London rrison & Sons. 37s. 6d. 
a Sa report of ScHIMMEL & Co. (FRITSCHE Bros.). Miltitz near Leip- 
zg. r2mo. pp. 161. New York: Fritsche Bros. 1906. e 
tt DALLA Torr, C. G. DE, and Harms, H., Genera Siphonogamarum ad systema 
Englerianum conscripta. Fasc. 9. pp.641-720. Leipzig: Wilhelm Englemann. 1907. 
M 6. 
12 SCHELLENBERG, H. C., Untersuchungen tiber den Einfluss der Salze auf die 
Wachstumsrichtung der Wurzeln, zuniichst an der Erbsenwurzel. Flora 96:474-500- 
6. 
