114 SUMMARY OF CURRENT RESEARCHES RELATING TO 



cellare, covering everything with dense masses of felt, several metres 

 in length, and as much as 2 cm. in thickness. Its power of attaining 

 such vigorous development on a substratum which does not afford the 

 least nourishment distinguishes this fungus from all others at present 

 known; and indicates that it must obtain its sustenance from the 

 particles suspended in the air of the cellar. It consists of a loose 

 tissue of branched hyphae from 2*5 to 3 /a in diameter, with occasional 

 irregular swellings. The filaments are provided with irregularly 

 placed indistinct septa, and a thick olive-brown membrane with 

 hooked or annular unevennesses, and strongly refractive contents. 

 The author found among the hyphse large masses of isolated spores, 

 of a narrow elliptical or almost club-shaped form, 6-13 /x long and 

 3-3 • 5 /A broad, of an olive-brown colour, simple or divided by a 

 single septum, and resembling the spores of Cladosporium. These 

 spores are formed on the apices of the young branches, and can be 

 made to germinate in water or solution of sugar. The author con- 

 siders it probable that BJiacodium is a stage of development of an 

 Ascomycete; but the asci and ascospores have not yet been detected. 



The effect of the exclusion of light on fungi which ordinarily 

 grovp- above ground is shown in the lengthening of the stipes and the 

 partial or complete abortion of the pileus ; many forms foimd in dark 

 places, and described by writers as distinct species, are modifications 

 of this nature of Lentinus lepideus and other species. To the same 

 category belong the various forms of Rhizomorph, which are modifica- 

 tions of Armillaria melleus and of other Hymenomycetous fungi; 

 those formed on dead willows and poplars, which are often much 

 branched, are usually derived from a species of Mycena. The black- 

 brown, horse-hair-like threads which frequently proceed from pine- 

 leaves, known as BMzomorpha setiformis, are the degraded fructification 

 of Marasmius cmdrosaceus. Of the same nature are the malformations 

 known as Oozonium, many of which belong to the cycle of development 

 of Merulius lacrymans. 



The author then describes in detail the remarkable fungus- 

 vegetation of the Hoymgrube near Czernitz, and concludes with a 

 description of Agaricus acheruntius, a species rarely found in woods, 

 and attaining its most luxuriant development in the uniform moisture 

 and temperature of underground passages. 



Development of Merulius lacrymans.* — Prof. R. Hartig has 

 carefully investigated the development of the fungus which produces 

 dry-rot in timber, and has been able to fill up several gaps in our 

 knowledge of it. It is exceedingly sensitive to cold, and. is hence 

 never found on living trees, but only in human dwellings. The 

 spores are so minute that about four million occupy a cubic mm. ; in 

 large quantities they form a light-brov^n powder; they contain a 

 drop of oil, and a small sharply-defined colourless spot, possibly a 

 nucleus. The germinating filaments are readily formed in nutrient 

 solutions, but do not undergo great development unless in contact 



* Hartig, E., ' Der achte Hausschwamm,' Heft i. 82 pp. (2 col. pis.), Berlin, 

 1885. Bot. Centralbl,, xsiii. (1885) p. 123. Cf. this Journal, v. (1885) p. 845. 



