292 M. C. Montagne's Organographic and Physiologic 



only*. An analogous instance, though in miniature, is found in 

 Oidium fructigenum . 



The colour of Agarics, Boleti, &c., has attracted the attention of 

 some observers. We will consider it both in the hymenium and 

 hymenophore. The colour of the hymenophore of Agarics and Bo- 

 leti is not constant in the same species ; it may be white, red, blue, 

 brown, olive and yellow (e. g. Russula emetica. Boletus scaber), with- 

 out any variation in the other characters. The colour of the hyme- 

 nium is less liable to vary in the same species, and when such a va- 

 riation does take place, it is usually due to advance in age. Thus, 

 in PratellcB, the gills are at first rose-coloured or violet, and at last 

 become black. In Coprini, from white or gray they pass to black 

 at the time of their deliquescence. As regards the proximate cause 

 of the colour of Fungi, it appears, after the observations of Morrenf, 

 that it is attributable to the presence of spherical corpuscles of yj^ 

 of a miliemetre circulating in the tubular filaments whose interlacing 

 forms the h)rmenophore, or free and dispersed in their interstices, 

 but not possessed of any motion in either case. Their colour is 

 more intense in proportion as they are nearer the outer surface of 

 the fungus ; that is to say, as they are more immediately influenced 

 by light. 



As to duration, it is ephemeral in a great number of Agarics ; 

 in the fleshy species it is in general from seven to fifteen days; 

 some, however, last longer. In the perennial Polypori it extends to 

 many years ; but these species increase by the successive production 

 of new layers, which every year are deposited on those of preceding 

 years. 



It is in this family that we find the most delicious Fungi, as, for 

 instance, Agaricus C(Ssareus(Cibus Deoriim, Clus.), or the true Oronge, 

 A. campestris, A. prunulus, Boletus edulis, &c. But amongst them 

 we find also the most violent vegetable poisons, and this even in 

 certain species which unhappily, without long study, are too easily 

 confounded with the most wholesome fungi. I cannot here enter 

 into any detail relative to the culinary preparation of good species, 

 or the means of remedying accidents caused by partaking of bad 

 fungi. On these points, the general works which treat on these 

 productions, or those which relate to toxicology or medicine, may 

 be consulted, and in particular ' Traite des Champ. Comest.' by 

 Persoon, or the treatises of Messrs. Roques and Cordier. The 

 article J^am, in * Dictionnaire universelle d'Histoire naturelle,' by 

 my friend and fellow-labourer Leveille, will also give valuable in- 

 formation on this head. There are still some uses to which these 



* This last explanation is admitted by Dutrochet, Observ. sur les Champ., 

 Ac. des Sc. Paris, 3 Mars, 1834. [It appears, from measurements which 

 have been accurately taken, that fairy rings increase annually in diameter, 

 •which accords with this notion, and the dark colour of the grass is doubtless 

 owing to the stimulating power of the mycelium. — M. J . B.] 



f See note on Agaricus epixylon, Bull. (^A. applicatus, Batsch), Acad. 

 Roy. Sc. de Bruxel., 5 Janv. 1839. 



