334 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
and bursts the oogone, the oosphere having previously been forced back 
into its ventral portion. 
Pithophora.* * * § — Prof. J. M. Moebius has examined a species of Pitho- 
phora (probably affinis ) from Brisbane. The akinetes contain a number of 
nuclei, even when mature, and differ from the corresponding structures 
in other Algas in being not formed simply by a modification of ordinary 
vegetative cells ; they are first of all separated, and have then a special 
mode of germination of their own after a period of rest. They are 
distinguished from the ordinary vegetative cells by having a thicker 
membrane and containing a large quantity of protoplasm and starch. 
Apparently the only mode of propagation of Pithophora is a non-sexual 
one. 
Halicoryne Wrightii.f — Prof. C. Cramer describes this rare Alga 
from the Loo-Choo Islands. Harvey placed it between Dasydadus and 
Neomeris, and Agardh, on account of its reproductive system, among the 
Acetabularieee. The author confirms Agardh’s conclusion by a study of 
the vegetative system, noting the calcification (chiefly in the outermost 
layers of the stem-cell and the fertile branches), the occurrence of 
alternate whorls of hairs and fertile branches, and the anatomical 
structure generally. His specimen was, however, without reproductive 
organs. 
Fungi. 
Function of the Nucleus in Fungi.! — Herr G. von Istvanffi has 
investigated the part played by the nucleus in various fungi belonging 
to the Mucorini, Saprolegniacete, Ustilaginese, Ascomycetes, and Basidio- 
mycetes. He asserts that it exercises an important function in the 
development of the fungus, especially in the formation of branches, 
which always originate in the neighbourhood of a nucleus. No conju- 
gation of nuclei takes place in the formation of the zygosperms of the 
Mucorini ; nor could this be determined to be the case in the Sapro- 
legniaceae. In all the Eumycetes there is a transitory period when the 
number of nuclei is very large, owing to their rapid multiplication. The 
migration of the nuclei in the formation of the fructification could 
generally be observed. The size of the nucleus varies greatly in the 
same species in different regions. The nucleus is, as a rule, multiplied 
directly by bipartition ; sometimes karyokinetic figures are formed ; 
occasionally there is a breaking up into a number of distinct portions. 
Assimilation of Nitrogen by Fungi.§ — From a series of experiments 
made chiefly on Penicillium glaucum and Aspergillus niger, Herr K. 
Puriewitsch concludes that the conditions under which they can absorb 
free nitrogen from the atmosphere are similar to those in bacteria, being 
dependent on the amount of sugar present in the nutrient fluid. 
Secretion-Receptacles of Fungi. |] — Herr G. von Istvanffi has detected 
lypical and well-developed conducting organs, hitherto unobserved, in 
* Ber. Deutsck. Bot. Gesell., xiii. (1895) pp. 356-61 (1 pi.). 
t 'Vieiteljahrschr. Nat. Gesell. Zurich, xl. (1895) pp. 265-77 (1 pi.). 
X Ber. Deutsch. Bot. Gesell., xiii. (1895) pp. 452-67 (3 pis.). 
§ Tom. cit., pp. 342-5. 
|| Termeszetrajzi Fiizetek, xviii. (1895) pp. 240-56 (German resume ). See Bot. 
Centralbl., 1895, Beili., p. 483. Cf. this Journal, ante , p. 214. 
