716 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
finds great differences in tlie intensity of respiration and assimilation. 
The greater the proportion of water which they contain, the more intense 
is the gaseous interchange with the atmosphere. Specimens from a very 
damp locality give off more gas than others of the same species living on 
dry soil. The reddish colour of many, increasing in abundant light, has 
the effect of diminishing the intensity of respiration and assimilation. 
Elaters of Hepaticae.* * * § — Miss Josephine E. Tilden describes the 
structure of the elaters in several genera of Hepaticae. When young 
they appear always to contain starch, which usually disappears when the 
spiral bands are formed, but sometimes remain in the mature elater. 
They not unfrequently branch. The branched elaters of Conocephalus 
conicus are specially described ; they occur also in Targionia, Anthoceros, 
and Badula. The branching does not take place until the pressure 
within the sporogone is relieved by the loosening of the spores and 
elaters, preparatory to their being set free. The number of spiral bands 
in the walls of elaters varies from one to five ; they display branching 
and fusion. In Conocephalus conicus there are, as a rule, two spiral 
bands, one or both of which generally branch. 
Revivification of Grimaldia.j — Sig. 0. Mattirolo has proved ex- 
perimentally that Grimaldia dicliotoma Raddi may survive being sub- 
jected to a very thorough desiccation for thirteen months, and states 
that other Marchantiacese will revive after having remained in a state of 
latent life in dry air for seven years. He brings together a number of 
analogous cases, refers to revival of desiccated animals, and bows before 
the problem. 
Characeae. 
Action of External Influences on the Characese.J — Herr J. Richter 
has carried out a series of experiments on the effects of changes in the 
environment of the Characeae, especially Chara fragilis and hispida. 
The shoots of both these species were found to be negatively geo- 
tropic and positively heliotropic. The curvatures take place chiefly 
in the young growing internodes. The removal of the apex retards 
the growth of the shoot. Rhizoids are produced on injured shoots when 
those already existing are removed. Even the smallest nodes can, when 
isolated, produce rhizoids. Their growth may be incited by surrounding 
the shoot with earth, or by darkening, but not by contact-irritation 
alone. The rhizoids are positively geotropic, but not distinctly helio- 
tropic nor aerotropic. The “ naked-footed branches ” are formed on 
shoots or separate nodes when these have been deprived of their normal 
growing point, or by covering up with earth ; “ pro-embryonic branches ” 
under similar conditions, but less frequently. The faculty of producing 
new shoots resides in the nodes only. C. fragilis will thrive in water 
containing 1 * 5 per cent, of sodium chloride. 
Monograph of Characeae.§ — Herr F. Filarszky has published a 
monograph of the Characeae, of which he makes forty-nine European 
* Minnesota Bot. Studies, 1894, pp. 43-53 (2 pis.), 
t Atti R. Accad. Lincei (Rend.), iii. (1894) pp. 579-84. 
x Flora, lxxviii. (1894) pp. 399-423. 
§ SB. K. Ung. Naturw. Gesell. Buda-Pest, Jan. 3, 1894. See Bot. Centralbl., 
lviii. (1894) p. 229. 
