ZOOLOGY AND BOTANY, MICROSCOPY, ETC. G15 



a certain phase the cytoplasm is differentiated into a transparent hyalo- 

 plasm which is not stained, and a stainable granular enchylema. This 

 latter takes the form of cylindrical cords, varying in number, imbedded 

 in the general mass of hyaloplasm. The enchylema alone contains 

 bodies which can be compared to nuclei ; and it appears to be only 

 within the cords that circulation of protoplasm takes place. Subse- 

 quently the enchylema undergoes an oily degeneration. 



Fertilisation of Peronospora parasitica.* — A detailed study of this 

 process has led Mr. H. Wager to the following general conclusions. 



The protoplasm of the oogone becomes differentiated into a central 

 vacuolate ooplasm and a granular homogeneous periplasm. Immediately 

 before this takes place, a receptive papilla is formed on the oogone at 

 the place where the antherid is in contact with it. At this spot the wall 

 of the oogone becomes very thin, and it is here that the fertilising tube 

 of the antherid penetrates the oogone. The nuclei of the oogone and 

 antherid undergo mitosis previous to fertilisation. A central body 

 becomes differentiated within the oosphere which appears to play some 

 part in bringing the sexual nuclei together, but disappears before the 

 fusion of a single nucleus which travels from the periplasm of the 

 oosphere and a single nucleus from the antherid which passes through 

 the fertilising tube. This fusion does not take place until the zygote is 

 nearly mature. The mature zygote is uninucleate. Of all the nuclei in 

 the oogone, one only is set apart for the purpose of reproduction, the 

 others remain in the periplasm, and are used up to form the protective 

 layer or layers of the oospore. No difference is observable between the 

 sexual nucleus and those which remain in the periplasm. They have 

 the same size and structure, and stain in a similar manner. Hence it is 

 probable that all the nuclei of the oogone are potentially sexual. 



There appear to be three distinct modes of fertilisation in the 

 Peronosporaceae : — (1) Uninucleate oosphere, binuclear fusion, and uni- 

 nucleate oospore (P. parasitica). (2) Uninucleate oosphere, binuclear 

 fusion, and multinucleate oospore (Cystopus candidus, C. Portulacse, 

 Peronospora Ficarise). (3) Multinucleate oosphere, multinuclear fusion, 

 and multinucleate oospore ((7. Bliti). 



Starch-corroding Fungi. f — Herr F. H. Billings dissents from the 

 opinion of Roze J that Amylotrogus, of which he describes five species as 

 having the property of corroding starch, is a reduced Myxomycete. He 

 finds no evidence of the existence of a plasmode ; the corrosion being 

 caused by hyphse belonging to an undoubted fungus. Other starch- 

 corroling fungi are Stysanus stemonitis, Trichocladium sp., Chsetomium 

 sp., Fusarium sp., and Coremium sp. 



New Genera of Fungi. — In a collection made by Ule in Brazil, 

 Dr. H. Behm § finds the following new genera : — 



Lindanella (Stictidearum). Apothecia innata, primitus globoso- 

 clausa, dein poro rotundo aperta et discum rotundum denudantia ; asci 

 cylindrici, 8-spori ; sporidia globosa, glabra, hyalina, 1-sticha; para- 

 physes fililormes. 



* Ann. of Bot., xiv. (1900) pp. 263-79 (1 pi.). 



t Flora, lxxxvii. (1900) pp. 288-98 (2 pis.). J Cf. this Journal, 1S97, p. 151. 



§ Hedwigia, xxxix. (1900) pp. 82 and 90 (3 figs.). 



