ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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ditions a saprophyte, but also occasionally acting as a parasite — forces 
its entrance into the tissues of the host-plant. Culture experiments 
convinced him that a substance poisonous to the host-plant is excreted 
in the germination of the fungus spores ; this excretion takes place 
especially during the early stages of germination. The secretion appears 
to consist of two substances, one of which causes changes in the cellulose- 
walls, the other the death of the protoplasm. Experiments showed that 
the latter is not oxalic or any other organic acid, but probably an 
enzyme. This fungus is able in this way to attack almost any plant, 
and almost any part of the plant. 
Similar results in the main were obtained with Mucor stolonifer and 
Penicillium glaucum, but the«latter species does not appear in the general 
way to produce a poisonous enzyme. 
Parasitic Fungi.— M. N. Raciborski * * * § finds, in Java, a disease pro- 
duced on Vigna sinensis by Cercospora Vignse sp. n. ; and the crops 
of Arachis hypogsea completely destroyed by a parasitic fungus, Septo- 
gloeum Arachidis. 
Dr. J. Eriksson f has studied in detail the life-history of Puccinia 
Bibis, which he regards as a true Micropuccinia, with only one genera- 
tion of spores, the teleutospores. The special form rubri attacks both 
the red and white currant, but not the black currant, and probably not 
the gooseberry. 
Mr. J. J. Davis { describes a new species of Doassansia, D. Zizanise, 
parasitic on Zizania aquatica. 
Returning to the question of the witch-broom of the barberry, Dr. J. 
Eriksson § agrees with Magnus in identifying it with Puccinia Arrhe- 
natheri , in which all three stages — the uredo, puccinia, and secidium 
stages — are facultative. 
Mr. A. D. Selby || records about 20 species of Cucurbitacese as host- 
plants of Plasmopara cubensis in Ohio. It is not known there on host- 
plants belonging to any other natural order. 
Dr. B. Frank % enumerates the various fungi and Schizomycetes 
which contribute to the potato disease, viz. : — PTiytoplithora infestans, 
Bhizoctonia Solani , Fusarium Solani , Phellomyces sclerotiophorus, and a 
Micrococcus which he describes as M. phytophthorus sp. n., and which he 
regards as the only one that is certainly pathogenous ; in addition to 
nematodes. The fungus parasites act either independently, or two or 
more in conjunction. A combination of Phytophthora and Bhizoctonia is 
especially common. 
Herr C. Wehmer** describes the structure and life-history of Monilia 
fructigena (which he regards as belonging to the genus Sclerotinia), one 
of the most destructive parasitic fungi of cultivated fruit-trees, and the 
cause of the brown -rot of cherries. 
The mildew of the apple, caused by Sphserotlieca Mali , is described by 
* Zeitschr. f. Parasitenkunde, 1898, p. 66. See Bot. Centralbl., lxxvi. (1898) 
p. 377. t Rev. Gen. de Bot. (Bonnier), x. (1898) pp. 497-506 (1 pi.). 
t Bot. Gazette, xxvi. (1898) pp. 353-4. 
§ Beitr. z. Biol. d. Pflanzen (Cohn), viii. (1898) pp. 1-16. Cf. this Journal, 1898, 
p. 659. || Bot. Gazette, xxvii. (1899) pp. 67-8. 
If Ber. Deutsch. Bot. Ges.. xvi. (1898) pp. 273-89. 
** Tom. cit., pp. 297-307 (1 pi.). 
