8 STRUCTURE OF AGARICS. 



the same end in view, and M. H. Hoffmann has given two parts, 

 which appear to ns to supply the actual wants of the science, which 

 has until now been a veritable gap. By the representation of the 

 specific type in its normal state, the study of its tissues, and of its 

 development, all three being presented, reveals some facts which 

 will facilitate the classification of the Agarics. The works of 

 Corda, before those of Hoffmann, have opened the way, for they 

 embrace all Fungi, and are produced more particularly from an 

 anatomic and physiological point of view. They have in this respect 

 rendered great service, and facilitate ulterior researches. 



Three principal parts together compose the vegetation of an 

 Hymenomycete — the mycelium, the receptacle, or hymenophore, and 

 the hymenium. 



I. The mycelium and receptacle, or hymenophore. — The mycelium, 

 the elementary composition of which is very simple, found under 

 the soil, or under the debris of dead leaves or branches, affects dif- 

 ferent appearances, generally white, sometimes yellow, and also red. 

 It is at times filamentous or silky {nematoid mycelium of M. 

 Leveille*), at times like felt (hymenoid mycelium of the same 

 author) ; finally, at times it becomes compact and solid, for a long 

 time regarded as a perfect fungus, and was called Sclerotium ; this 

 is the scleroid or tuberculous mycelium of M. Leveille. This 

 author has also signalised the malacoid, or pulpous mycelium be- 

 longing to some Physariacei, or to some Trichiacei, the fungoid 

 nature of which is actually contested. -j - 



The nematoid mycelium, which is more frequently found amongst 

 Agarics, varies extremely in appearance, at times presenting itself 

 like some rayed threads of silk, and prickly, at times ramified or 

 dichotomous, like some radicular fibres, and at times so thin that it 

 is easily pulverized ; it certainly has its characteristic value. Hoff- 

 mann, draws from its absence, or its concrete form, a conclusion 

 which appears to us quite just. " That there is more difference," 

 says this author, " than the kind of development in Amanita with- 

 out a mycelium, which recals the Gasteromycetes, and among which 

 the mycelium is replaced by the veil, and some Agarics, with a per- 

 manent mycelium in the form of Sclerotium, as for example, Agari- 

 cus tuberosus."X One can, perhaps, place more value on the per- 

 manence or annual disappearance of the mycelium, than to the per- 

 ennial, or to the annual or biennial life of the stem of Phanerogams, 

 where the form of the organs of vegetation so notably differ, it 

 follows that they are monocotyledons or dicotyledons, the mycelium 

 may affect different modes of development, as in the two examples 

 cited by Hoffmann. 



The concrete mycelium or sclerotium is rather scattered amongst 



* " Annales des Sci. Nat," 2nd ser., t. xx.,p. 78, &c. 



f The observations of Wigand (Pringsheiin's Jahrbucher) appears to me to 

 shake strongly the hypothesis of M. de Bary, as to the animal nature of these 

 small productions. 



% Hoffmann, Icon. Analyt. Fung., Heft.i, 1861. 



