ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
67 
(2) Nutrition and Growth (including' Germination, and Movements 
of Fluids). 
Parasitism and Multiplication of Cynomorium.* * * § — Sig. U. Martelli 
has examined the mode of attachment of Cynomorium coccineum to the 
root of the host-plant. He finds, as in other parasitic plants belonging 
to the Balanophorace© and Rafflesiace©, a thallus belonging to the 
parasite, and a perforating cone of tissue in which are contained a 
large number of vessels irregularly disposed and in direct contact with 
the tissue of the host. In addition to this penetrating cone, rows of 
cells belonging to the parasite penetrate into every part of the woody 
tissue of the host, and especially into the cortical tissue of the root ; 
these cells are very frequently of a rose colour. The germinating 
seeds of Cynomorium develope into a thallus in contact with the tissue of 
the host ; but, in addition to this the plant has another mode of propaga- 
tion. The stem puts out root-like organs in pairs, some of which are 
provided with root-caps, and are undoubtedly true roots ; while others 
develope into propagula or gemmae destined to develope into new in- 
dividuals. 
The substance of which the cell-wall of Cynomorium is composed 
resembles that of fungi in resisting attacks of sulphuric acid. A 
mycorhiza was observed in the cells of the thallus. 
Vitality of Annual Plants. t — Mr. T. Holm records a number of 
examples of American plants, ordinarily annual, which become perennial 
under exceptional conditions. They include Hypericum nudicaule, 
Delphinium Consolida, Cyperus flavescens, Car ex cyperoides, and several 
species of Gramine© and Crucifer©. Biennial species also sometimes 
produce flowers the first year. 
Growth of the Cell-wall of Root-hairs.| — Herr E. Zacharias has in- 
vestigated the mode of growth of the cell-wall of root-hairs, especially 
in the cases of Cliara and of Lepidium sativum. He finds, from ex- 
periment, that mechanical irritation has no effect in producing thicken- 
ing of the cell-wall. The thickening takes place at the apex of the 
hair, and it is here only that the surface increases under normal con- 
ditions. The thickening-layers must be regarded as new formations 
which become deposited within the membrane previously in existence. 
The author agrees with Askenasy § rather than with Wortmann, that, 
although turgor is a necessary condition of growth, it is not the prime 
factor in causing it ; this is dependent on the properties of the proto- 
plasm itself. He is now of opinion that particles of protoplasm become 
inclosed in the layers of cellulose. 
Grafting on underground parts of plants. ||— M. L. Daniel has made 
a series of experiments in grafting, on roots and tubers. As a general 
rule he finds that it is, in many cases, easy to obtain a graft on a root 
or underground stem of a plant nearly allied to the graft-plant, and, in 
some cases, even on a species belonging to a different natural order, 
* Malpighia, v. (1891) pp. 97-105 (6 pis.). 
t Amer. Journ. Sci. (Silliman), xlii. (1891) pp. 304-7 (1 pi.). 
% Flora, xlix. (1891) pp. 466-91 (2 pis.). Cf. this Journal, 1891, p. 501. 
§ Cf. this Journal, 1890, p. 630. 
|| Comptes Rendus, cxiii. (1891) pp. 405-7. 
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