564 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Characeae. 
Shoot-Nodes of the CharacesD.*— Pursuing liis investigation on 
this subject, Dr. K. Giesenhagen now describes in great detail the 
structure of the shoot-nodes in the following species : — the rare Nitella 
cernua, where, in accordance with its gigantic size, the nodes are com- 
posed of a very large number of cells, Tolypella , in all the species of 
which genus the development of the nodes corresponds closely to that 
in Nitella syncarpa , Lamprothamnus alopecuroides, and Chara stelligera. 
Muscinese. 
Propagation of Mosses by Gemmae, j — Herr C. Correns gives further 
details respecting the propagation of mosses from nematogenous cells. 
In those species which have no persistent growing point, there are 
certain cells which alone possess the property of forming protonemes. 
These occur in all parts of the plant which do not become spontaneously 
detached; — in Hypnum stramineum on the under side of the leaves; in 
Leucobryum vulgar e especially on the upper side of the leaf and on the 
margins of the apex ; in many species from the meristematic cells of 
the base of the leaf. In dissected moss-stems the rhizoids are usually 
produced from nematogenous cells. This property does not appear to 
belong to all the cells of the plant indifferently. 
Gemmae .of Aulacornnium androgynum.f — Herr A. Y. Grevillius 
supports the view that the clusters of gemmae or bulbils found at the 
apex of the naked jiseudopodes of this moss are modified leaves. A com- 
plete series of transitional forms occurs between them and typical foliage- 
leaves, and the author cannot confirm the view of Correns § that in this 
species these organs arc modified paraphyses, while in A. palusire they 
are modified leaves. In both species neither the apical cell nor the 
rows of cells immediately beneath it takes any part in their germination. 
Dwarf Male Plants of Dieranum.|| — Herr C. Warnstoff finds the 
dwarf male plants which grow from the stem of the female jdant in 
the following species of Dicranum : — spurium, undulatum , Bonjeani , majus, 
and scoparium. They are not produced on a protoneme which springs 
from a spore, but on the weft of roots which serves as a protoneme. 
They carry on their existence in direct connection with the female plant, 
and replace male “ flowers ” ; and the author proposes for this “ inflores- 
cence ” the term “ pseudo-autoecious.” He has found ordinary male 
plants in D. scoparium and majus , but not in D. spurium , Bergeri, undu- 
latum , Bonjeani , neglectum , or Muhlenbechii. 
Algae. 
Food-Materials of Algge. — Herr W. Benecke % confirms the state- 
ment of Molisch of the indispensability of calcium for the active growth 
of the lower algae ; potassium he also finds to be essential, but the pro- 
portion in which this element is present is comparatively indifferent. 
* Flora, lxxxv. (1898) pp. 19-65 (2 pis. and 18 figs.). Cf. this Journal, 1897, p. 416. 
t Ber. Deutsch. Bot. Gesell., xvi. (1898) pp. 22-7 (1 fig.). Of. this Journal, ante, 
p. 105. % Tom. cit., pp. 111-18 (1 pi.). 
§ Cf. this Journal, ante , p. 105. 
|| Allg. Bot. Zeitschr., 1898, pp. 40-3. Sec Iledwigia, xxxv. (1898) Rep., p. 129. 
1 Bot. Ztg., lvi. (1898) l te Abt., pp. 83-97. Cf. this Journal, 1895, p. 545. 
