962 XIII. rUNGI. 



Ascophora Mucedo develops principally upon neglected vegetable substances, bread, sweetmeats, &c. ; 

 its spores germinate in ten to twelve hours. Mueorcanimis forma tufts on dog's excrement ; its sporangium 

 tears irregularly. Mucoi- nitens, better known under the name of Phycomyces, vegetates on fat, and bodies 

 steeped in oil, as linen, wood, and earth. It is the giant of the Mucedinece ; its filaments attain 

 four inches in height ; they are as lustrous as silk, preserve well, and do not stick to paper. Agardh 

 first described it under the name of TMva nitens. Syiygiiei inegalocarpus, which grows only on Fungi, is 

 remarkable for its mode of fertilization, which is analogous to that which takes place in the conjugate 

 Algm. The same phenomenon is observable in Ascophora rhizojms. Philohus is a small Fungus which 

 grows, especially in autumn, on the excrement of nearly all animals; its life is very brief; it grows 

 during the night, and disappears in the middle of the day. It resembles a small pedicelled urn 

 covered with an operculum ; the sporangium is sunk in the cavity of the receptacle) whence it emerges 

 by throwing off the operculum to a distance, and as it usually ruptures, its vestiges only are found, which 

 has led to the belief that the operculum was the sporangium itself, and that it contained the spores. 

 These spores move and swim, so to speak, in the sporangium before their emission, a phenomenon which 

 is perhaps unique, and which ought to be followed throughout all its stages. 



Tbibe V. TBIGEOSPORH^. 



Receptacles filamentous, simple or branched, fistular, continuous or chambered. 

 Spores very various in form, simple or compound, clustered at the extremity of the 

 branches, or around the receptacle. 



PEINCIPAL GENEEA. 



Ceratium. Menispora. Polyactis. Periconia. Arthrinium. 



Botrytis. Sporocybe. Gonatotrichum. ^ Peronospora. Pachnocybe. 



Psilonia. Verticillium. Asterophora. Haplaria. Helicotricbum. 



Mycogone. Desmotrichum. Helicoma. Sepedonium. Gonytrichum. 



Helminthosporium. Acrothamium. Rhopalomyces. 



This tribe is certainly one of the. most curious to study; the numerous genera which compose it 

 grow on decomposing vegetable matter, and even in the tissue of living leaves ; hitherto they have not 

 been found to have any useful quality, and unfortunately two species are notorious for the mischief they 

 have caused to agriculture and industry. Ceratium hydnoides, of which the structure is extremely delicate, 

 in damp weather sometimes covers old rotten trunks with its white tufts. 



Sepedmiitim mycopliilum is remarkable for converting the whole substance of Boleti into a brilliant 

 golden yellow dust. Botrytis Bassiana is the cause of the Muscardine, a disease which for the last twenty 

 years has devastated the silkworm nurseries ; it is developed on several caterpillars, but especially on the 

 silkworm. Its mycelium attacks the interior of the living catei-pillar, which it finally kills; twenty-four 

 hours after its death the Fungus appears like a little forest on the surffjce of the worm, which looks as 

 though covered with flour or plaster. All means devised against the ravages of the Muscardine have 

 proved fruitless ; and just as it was disappearing, it was replaced by the spot or pdbritie, a still more fatal 

 disease, which some naturalists consider to be of vegetable origin. Peronospora infestans has since 1845 

 shown itself in all countries where Potatos are cultivated, and produces the rot. The disease first shows 

 itself on the leaves, which curl, turn black, and dry up. The spores of the Fungus which occupies the 

 lower surface of the leaves, become detached, are washed into the earth by rain, and reach the tubers, 

 on which they begin to grow, forming superficial patches which each day in&rease in diameter and 

 depth, till the tuber finally decays.' As in the case of the Muscardine, the remedies prescribed for this 

 disease have proved absolutely useless. 



' This is not always the case, as the disease fre- stroy the haulm. The disease is propagated still more 

 quently commences -within the tuber; the spores which rapidly by zocspores, which are occasionally produced 

 fall on the stem also gei-minate there, and quickly de- within the spores, as first observed by De Bary. — En. 



