ZOOLOaT AND BOTANY, MICROSCOPY, ETC. 539 



where the ordinary rule is departed from. The " inverse " hymenium 

 is not uncommon in the Agaricini. Hydnum compactum and species 

 of FistuUna may have hymenophorous tubes or projections on the 

 upper side. The upper part of the stipes of many species of Boletus 

 has reticulate structures which are a true hymenium. If the pileus 

 does not afford sufficient protection for the development of the 

 spores, it remains sterile, as in Polyporus annosus. P. alutaceus and 

 Trametes suaveolens occasionally produce organs of fructification on 

 the upper side. Although most Hymenomycetes require the protection 

 of a jjileus, the Clavariei do not. The Pezizce seem to need the 

 assistance of water, which the Agarici avoid ; the Lycoperdacei 

 surround their organs of fructification with a resisting enveloj)e ; in 

 the Sphasriacei this envelope is hard and carbonaceous. 



Chemistry of " Fairy-Rings."*— Sir J. B. Lawes, Dr. J. H. Gilbert, 

 and K. Warington have continued their investigations as to the 

 causes of the rings of luxuriant grass which are always more or less 

 connected with the appearance of fungi. They consider that there is 

 no doubt that the source of the nitrogen of the fairy-ring fungi is the 

 organic nitrogen of the soil itself, which they assiinilate, presumably, 

 though not certainly as organic nitrogen, and eventually deposit as 

 manui'c which becomes available to the associated herbage. Immedi- 

 ately outside the ring the turf is generally found penetrated by a 

 white cobweb-like mycelium extending to a depth of several inches, 

 and sometimes even to a foot or more. 



Fungus-Parasites of the Aurantiaceae.f — While previously only 

 34 species of fungus had been described as parasitic on the orange, 

 lemon, citron, and allied trees, 0. Penzig now brings the number up 

 to 153, including exotic forms, 54 of which are new. Some of these, 

 as BMzodonia violacea, Sphcerella Gibelliana, and Meliola Penzigi, 

 entirely destroy the crop; while others appear only sporadically, 

 but are always injurious. Each species is described in detail, with 

 Latin and Italian diagnosis, an account of its habitat, literature, 

 synonymy, &c., with various biological and critical notices. Colom-ed 

 nature-printed illustrations of 136 species are given. 



''Ozonium." :]; — C. Eoumeguere has investigated the connection 

 between the old genus Ozonium and the filamentous mycelium of 

 various hymenomycetous fungi. He finds that it may belong to no 

 less than eleven species, viz. nine of Coprinus, one of Lenzites, L. 

 trahea, and one of Craterellus, C. muscigenus. He is unable to confirm 

 the statement that has been made, that "conidia" are formed on the 

 ozonium. The white or fawn-coloured byssoid portion which forms a 

 kind of puffiness of the base of the stipes of Coprinus on the surface 

 of the ozonium is a form of sclerotium from which the Copinus 

 springs. The external layer of this sclerotium is composed of 



* Journ. Chem. Soc , xliii. (1883) pp. 208-23. 



t Penzig, O., 'Fimghi agrumitoli. Contrib. alio studio dei funghi parassiti 

 degli agrumi,' 12'i pp. (136 pis.) Padua, 1882. 



X Reunion des dele'gues des Soc. sav. a la Sorbonue, March 28, 1883. See 

 Bot. Centralbl, xiv. (1883) p. 62. 



