Sketch of the Class Fungi. 115 



which are mere lacunae, contain peridiola in which are enclosed the 

 Sporidia, which are often filled with sporidiola ; others, larger, are 

 lined with a membrane or hymenium, composed of juxtaposed cells. 

 It is in the interior of these cells tliat the sporidia are contained in 

 the genus Genea, and from between them that those of the genus 

 Rkizopogon emerge. In some other utero-hymenian genera, the 

 sporidia are borne by a minute peduncle, which is formed at the 

 summit of the basidia. In the genera Pachyma and Picoa, where 

 there is no trace of veins, the peridiola nestle here and there in the 

 flesh of the fungus. 



The sporidia of the Tuberacece are then generally contained in 

 asci or peridiola. They are seldom smooth, more rarely striated 

 longitudinally. Almost always, on the contrary, they are rough or 

 echinulate, a circumstance which made Turpin regard them as the 

 truffle in miniature. \'ittadini, who has studied the germination of 

 those oi Elapkomi/ces*, which are echinulate, has seen these points 

 elongated into byssoid filaments, which at length envelope the seed 

 in a thick down. This down, according to ♦'he author, is as it were 

 the cotyledon of the j'oung plant. He infers by analogy, that the 

 same is the case with the sporidia of most other Tuberacece. The 

 fungi, which generally are subterraneous, prefer temperate climate, 

 and are found especially in forests of oak and chestnut. Truffles, 

 known to Theophrastus under the name of oloroj', and to Plutarch 

 under that of iJoiof, have long been esteemed for their delicious 

 flavour. Everybody knows that they are nutritive and aphrodisiac, 

 and that pigs are quite as fond of them as ourselves f. 



We come now to the PhulloidetE. The species which compose 

 this tribe, though we derive no immediate benefit from them, are 

 nevertheless worthy of arresting for a moment our attention, because 

 they form a very evident passage from true Gasteromycetes to Hyme- 

 nomycetes ; they approach the latter by the constant presence of a 

 volva, but especially by the structure of their hymenium. This 

 structure indeed has been observed only in the genus Phallus ; but, 

 till new investigations show us the identity of structure in the other 

 genera, analogy leads us to suppose that it does not differ in the 

 rest of the tribe. It is to Mr. Berkeley again that we are indebted 

 for this interesting discovery. What he has seen in Phallus caninus 

 is as follows : as in the puff ball, the fructiferous membrane is 

 formed of a verj' sinuous hymenium. The walls of these sinuosities 

 are composed of elongated cells, a little clavate at the tips, and sur- 

 mounted by from four to six threads, each bearing an oblong spore 

 (Berk. /. c. p. 164. t. 2. f. 22, 23). The basidia ajjpear all to be 

 fertile and of an equal length. We have then here an Hymenomycete 

 which is distinguished from the others merely in the sporidia being 

 soon involved in a mucilaginous mass derived from the hymenium. 



* See, on the subject Elaphomyccs, Messrs. Tulasne'ss admirable paper, 

 Ann. Sc. Nat. July 1811. — M. J.B. 



f Many other species of tliis tribe are eaten. In the Canaries, a species 

 is much esteemed which I have referred doubtfully to Jthizopoyon alhus, 

 Fr.,but wliich is perhaps Tuber niveitm, Desf., a species at present unknown. 

 Hist. Nat. Caiiar. Phvtogr., sect. ult. p. 85. 



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