1876.] Botany. 871 
BOTANICAL PAPERS IN Recent PERIODICALS. — Comptes rendus, 
No. 9. . Boussingault, On the Influence exerted by Vegetable Mold on 
the Nitrification of Nitrogenized Substances used as Manures. S. 
Cloéz, On Elæococca Oil, and its Modification by Light. Ed. Heckel, 
On the Movements of the Hairs and Glands of the Leaves of Drosera 
rotundifolia, and in the Leaves of Pinguicula vulgaris. No. 10. A. 
Barthélemy, On the Absorption by Plants of Bicarbonates in Natural 
Waters 
Flora, No. 5 and continued in No. 6. Dr. H. Müller, On Heliotrop- 
ism. (The following conclusions are reached: (1.) In a growing organ 
of a plant only those zones which have not yet finished growing, exhibit 
curvatures dependent on light. (2.) The heliotropic curvature is pro- 
duced by al the sensitive zones during extension. (3-) The parts which 
grow most rapidly are most sensitive to light. (4.) Even negative 
heliotropism (curvatures away from the light) as in roots is most mark 
when growth is most vigorous. (5.) Heliotropic curvatures do not cease 
at once when the light is removed. (6.) The rate of the curving is slow 
at first, then is accelerated, reaches a maximum, after which it dimin- 
ishes. (7.) The curvature is not always at the same place ; it recedes 
gradually towards the lower end of the growing stem. (8.) The 
smaller the angle which the incident rays of light make with the axis 
of the stem, the slighter will be the effect produced. (9.) Heliotropism 
continues until growth ceases or until light has been brought to act upon 
two sides of the plant, or until the curvature from light is overpowered 
by curvature from gravitation (geotropism). (10.) Heliotropic curva- 
ture, under similar circumstances, increased with intensity of light. (11.) 
Stems which have been previously kept in the dark are more sensitive 
to light coming from one side, than are those which have been previously 
illuminated on all sides. (12.) The concave side, which is the one most 
highly illuminated, grows less rapidly than the other. (13.) Negative 
curvatures are not accompanied by uniform growth throughout all zones 
but are characterized by growth only in the lower zone. (14.) Helio- 
tropic curvatures are more rapid when geotropism is excluded. (15.) 
Geotropism counteracts heliotropism, to differing degrees in different 
Plants, (16.) Certain parts or stems are sensitive to light, and others 
are highly geotropic. (17.) Some negatively heliotropic roots are hin- 
dered in growth when they are illuminated on all sides.) X. Landerer, 
of Athens, Botanical Notes from Greece. No. 7 and 8. Hugo de Vries, 
On Wood Repairing Wounds (continued). J. Sachs, On Reinke’s In- 
Vestigations respecting Growth. (Alleging that what Reinke has lately 
published in regard to a new instrument for measuring rate of growth 
Suppresses the fact that the method used is substantially that employed 
Y Sachs.) A. Geheeb (noticing mosses from near the Rhone). 
Botanische Zeitung, No. 11. Ph. Van Tieghem, New Observations 
respecting the Development of the Fruit and the supposed Sexuality 
