ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
635 
Respiration of Roots.* — Mr. J. Bancroft figures the aerial roots of 
a number of shore-plants, and describes their function in assisting in the 
respiration of the plant. 
y. General. 
New Insectivorous Plant. f — Dr. D. D. Gonzalez describes the struc- 
ture of the gigantic flowers of Aristolochia grandiflora of Central America. 
The swollen base of the corolla-tube forms a hollow chamber, within 
which are found countless numbers of the dead bodies of insects, in 
various stages of decomposition. He believes that these are actually- 
digested, and the products absorbed into the tissues of the plant, though 
he is not yet able to describe the pepsin-producing glands by means of 
which the digestion is effected. 
Atavism of Plants.J — MM. le Baron d’Ettinghausen and Prof. 
Krasan call attention to the heteromorpliism in the form of the leaves 
of the oak and the beech when injured by excessive cold, or by the 
attacks of caterpillars or other insects. Under these conditions the 
injured branches frequently put out shoots which bear leaves very 
different in form and size from the normal leaves of the species, or of 
other existing species of the same genus, and more or less resembling 
those of extinct species ; and the authors regard this as an illustration 
of atavism or reversion to an ancestral type. 
Adaptation of Grasses to Dry Climates.§ — Herr E. Hackel describes 
the peculiarities by means of which, in addition to the anatomical cha- 
racters of the leaves, grasses are enabled to flourish in a very dry climate. 
These are mainly two, viz. : — (1) The formation of bulbs or tubers on 
the lower part of the stem, frequently on as many as three or four of the 
lowest internodes; (2) The formation of “tunics,” i. e. of a number of 
dry sheaths surrounding the lowest internodes which are thrown off in 
succession. A list of grasses is given which display each of these cha- 
racters, and the special arrangements are described in detail. 
Value of Chlorine to the Plant. || — Herr C. Aschoff gives the per- 
centage of chlorine in different parts of the seed and seedling of 
Phaseolus multijlorus , P. vulgaris , and Zea Mays , and deduces, as the 
result of a series of experiments, that chlorine is an essential constituent 
of the food-material of these plants. 
“Pock-disease” of Tobacco.1T — Herren D. Iwanowsky and W. 
Poloftzoff have determined that the disease known by this name, which 
is very destructive to tobacco-plantations, appearing as brown spots or 
streaks on the leaves, is not due to the attacks of a parasitic fungus, but 
either to excessive moisture in the soil or to sudden evaporation after 
wet weather. It occurs also on allied plants, such as Datura Stramonium 
and Hyoscyamus niger, and is probably widely distributed through the 
vegetable kingdom. 
* Kep. Australasian Assoc, for the Advancement of Science, 1889, pp. 327-3. 
(10 pis.). See Bot. Centralbl., xlii. (1890) p. 311. Of. this Journal, 1887, p. 111. 
f Journ. de Micrograpkie, xiv. (1890) pp. 109-13. 
X Arch. Sci. Phys. et Nat., xxiii. (1890) pp. 76-81. 
§ Yerhandl. K.K. Zool. Bot. Gesell. Wien, xl. (1890) Abhandl., pp. 125-38. 
|| Landwirthsch. Jahrb., xix. (1890) pp. 113-41 (3 pis.). See Bot. Centralbl., xlii 
(1890) p. 212. 
11 Mem. Acad. Imp. Sci. St. Petersbourg, xxxvii. (1890) 24 pp. and 3 pis. 
