126 SUMMARY OF CURRENT RESEARCHES RELATING TO 



formed laterally or terminally on the hyiilife by the transformation of single 

 hyphal cells, and detached themselves from the hyphal cortex of the so- 

 redium. These detached conidia readily germinated in the surrounding 

 water. If the germinating filament came into contact with an isolated 

 cell of Hormidhim, it completely invested it, branching abmidantly, the 

 algal cell dividing at the same time, under the influence of the parasite, into 

 four, eight, or sixteen, thus giving birth in a short time to a new soredium. 

 If the germinating filament came into contact with a filament of Hornndium, 

 the latter also became completely invested, and the cells of the filament 

 separated and broke up into the coccus form, thus furnishing the gonidia 

 for the new soredia. 



Micro-cliemistry of Lichens.* — Herr K. B. J. Forsell has tested a 

 number of lichens and fungi for liguin by the phloroglucin and hydro- 

 chloric acid test, but in all cases with negative results. Some lichens, as 

 Loharia pulmonaria and Lecanora pnllescens, toc)k sooner or later a red tinge 

 with iudol and sulphuric or hydi-')cbloric acid ; but since the same result 

 was obtained with potato-starch, gum arabic, cotton, and cane-sugar, this 

 cannot be regarded as a reliable test for lignin. The author found that 

 the hyphfe of lichens occasionally took a slight red tinge with sulj)huric 

 acid alone, without indol. This the author explained by the conversion of 

 the lichenin into sugar by the acid, the sugar then giving Easpail's reaction 

 with the acid in the presence of albuminoids. 



Fungi. 



Cell-nuclei in the Hymenomycetes.f — M. L. K. Eosenvinge has ex- 

 amined a large number of species of Hymenomycetes, with the object of 

 determining the presence or absence of a nucleus in the cells. The staining 

 reagent used was hematoxylin on material hardened in alcohol, but its 

 use was often attended -ndth difiiculties. 



The author finds tliat, as a general rule, all the cells of the Hymeno- 

 mycetes contain nuclei, though, under certain circumstances, they may 

 disajipear with the protoplasm. In the adult cells of the ordinary hyphae 

 there are generally several nuclei ; in the young cells there is probably 

 only one, at least in some si)ecies. In the young basidia there is always 

 only one. The cystidia also contain at first only a single nucleus, which 

 may subsequently divide into several. A nucleolus can always be de- 

 tected, especially in the nuclei of the basidia. In some genera the nucleus 

 has a vesicular appearance, the chromatin accumulating at its periphery. 

 The only case in which an indication of indirect division of the nucleus 

 was observed by the author was in the basidia of Triclioloma virgatum. 

 The nucleus of the basidia ordinarily divides into four or eight, double 

 the number of the sj^ores, which are formed all at the same time. The 

 j)rotoplasm and the nuclei pass from the basidium into the spores, which 

 thus contain either one or two nuclei. If the spore contains only a single 

 nucleus, its diameter considerably exceeds that of the sterigma. If it has 

 two spores, these are smaller, their substance also being less dense. The 

 change of form of the nuclei, in passing into the spores, is passive, being 

 caused by the obstacle offered by the cell-wall of the sterigma. 



The mode of formation of the sj)ores in the Hymenomycetes is an 

 example of cell-division. The two or four (rarely three or six) daughter- 

 cells are formed in the lower part of the basidium or mother-cell, the 



* SB. K. Akad. Wiss. Wien, xliii. (1886) pp. 219-30. 

 t Aim. Sci. Nat. (Bot.), iii. (1886) pp. 75-93 (1 i)l.). 



