218 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Chloraster. Body variable in form, with four more or less projecting 
sides ; protoplasm green ; one pigment-spot ; icilia five, one central 
one, surrounded by the four others arranged as a crown. Two species, 
C. gyrans Ehrb., C. agilis Kent. 
Wittrock and Nordstedt’s Algge aquae dulcis.* * * § — The last three 
fasciculi (Nos. 851-1000) of this publication include specimens of the 
following new species: — Trentepohlia recurvata W. and N., Cladophora 
Nordstedtii Hauck, G. Arechavaletana Hauck, from Uruguay, Mougeotia 
gelatinosa Wittr., S. Lagerheimii Wittr., from Sweden, Cosmarium 
suhstriatum from Lapland, Hydrocoleum platense Nordst., from Uruguay. 
Fungi. 
Thermogenic Action of Fungi.| — Prof. F. Cohn discusses the cause 
of the elevation of temperature which always accompanies the germina- 
tion of seeds, as, e. g. the malting of barley. The difference may 
amount to as much as 17°, and may raise the temperature to as much as 
60° C., causing the death of the seeds. Prof. Cohn rejects the theory 
that this elevation is due to intramolecular respiration, J which may con- 
tinue even after the death of the seed. He believes it to be due entirely 
to a process of fermentation. The fungi which are the causes of the 
earlier stages of this phenomenon, species of Penicillium and Phizopus, 
are themselves killed by the high temperature, and it is then carried on 
entirely by Aspergillus fumigatus, which has the power of resisting a 
very high degree of heat. The highest temperature is reached only 
when the fungus begins to fructify. 
Mycorhiza.§ — Herr A. Schlicht describes the occurrence of mycorhiza 
in a number of plants in which it had not previously been observed, 
such as, e. g. Paris quadrifolia ; while young roots are often completely 
free of the fungus, older roots are always at least partially infested by iL 
The hyphas penetrate through the intercellular substance of the epidermal 
and hypodermal cells into the large thin-walled cortical cells, and there 
develope into masses which are in connection with the environment of 
the root, and with one another by filaments which perforate the septa. 
The spots which are thus infested have quite the same structure as the 
uninfested spots; the fungus is not a parasite, and has no injurious 
influence on the root. Similar phenomena were observed in Banunculus 
acer and other species of the genus, Caltha palustris, Holms lanatus, and 
other grasses. Leontodon autumnalis is infested by an endotrophic 
mycorhiza, such as is found in other Composite, Umbelliferse, Rosaceae, 
Gentianaceae, &c. 
Roots infested with endotrophic mycorhiza more closely resemble 
normal roots than those with the ectotrophic, which often develope into 
coral-like tubers. 
In a large number of natural orders some of the species are ordinarily 
attacked by mycorhiza, while others are entirely free from it. It was 
* Bot. Notis., 1889, pp. 157-68 (6 figs.). 
t JB. Schles. Geseil. Vaterl. Cultur, 1888 (1889) pp. 150-6. 
X Cf. this Journal, 1887, p. 619. 
§ ‘ Beitr. z. Keuntuiss .... cler Mykorhizen,’ 8vo, Berlin, 1889, 35 pp. and 1 pi.. 
Sec Bot. Centralbl., xl. (1889) p. 383. Cf. this Journal, 1889, p. 422. 
