HYMENOMYCETES 143 



pileus, and peculiarities of structure which prohibit its unison 

 with Corticium ; Michenera, with a placentiform habit, a waxy 

 hymenium, and pedicellate spores ; and Exdbasidium and Helico- 

 hasidium, which are encrusting and waxy, growing upon living 

 plants, and distorting them. Finally, Cyphella, having the form 

 of Peziza but the fruit of Corticium, being in fact a cup-shaped 

 Corticium ; and Solenia, the cups of which are elongated into 

 tubes, so that it seems doubtful whether they should be placed 

 in relationship with Poria, in Polyporeae, or with Cyphella in 

 Thelephoreae. 



Briefly and succinctly, these are the principal genera of 

 Thelephoreae, but before dismissing them we must advert to 

 certain appendages of the hymenium which 

 distinguish some of the genera above 

 enumerated. In addition to the basidia 

 there are to be found in the genus Penio- 

 phora stout projecting cells, which are either 

 the modified cystidia, or analogues of cystidia, 

 but which have been called metuloids. 

 They are fusiform, colourless, and at first 

 smooth, but afterwards rough and brittle fig. 58.-Cystidia of 

 from the deposit of oxalate of lime on 

 their surface. These are conspicuous objects upon the otherwise 

 smooth hymenium, giving it a velvety appearance, and by 

 this character separating the species from Corticium. In 

 another genus, that of Hymenochaete, the same place and posi- 

 tion on the hymenium is occupied by projecting, acute, non- 

 septate brown bristles, which spring from the hyphae of the 

 subiculum, and impart also a velvety appearance. Exter- 

 nally in habit the species resemble Stereum, but they are 

 readily distinguished by the presence of these brown project- 

 ing bristles. A similar kind of appendage to the hymenium 

 has been detected in some species of the Polyporei, for which 

 the generic distinction of Mucronoporus has been proposed. 

 In a small section of the genus Hymenochaete, according to 

 Saccardo, but generically separated by Cooke and by Massee 

 under the name of Veluticeps, the hairs of the hymenium are 

 produced generally in bundles, and are flexuous and septate, 

 in which respect they differ from the setae of Hymenochaete. 



