INTRODUCTION TO CRYPTOGAMIC BOTANY. 237 



227. Wo have here, therefore, some first excejitions to the 

 hysterophytal or epiphytal habit of many Fungi. But not only 

 must we make exception for such Fungi as imitate Alga? or 

 Lichens, in deriving nutriment from the surrounding medium ; 

 a further exception must be made in favour of a considerable 

 quantity of species which really live on inorganic matters. 

 Now, it is true of many epigeous species, that, like similarly 

 situated Phoenogams, they live on matter derived from the 

 solution of humates or ulmates contained in the soil, and as 

 these result from the decomposition of organic matters, prin- 

 cipally or originally derived from the vegetable world, they 

 are really hysterophytal. But, allowing this, it must still be 

 confessed that there are many species which seem to live on 

 mineral matter. There are, for instance, numerous exotic 

 Polypori, which grow on volcanic tufa or on exposed soil, in 

 which a very small quantity only of organic matter, if any, can 

 be supposed to be present. Coprinus radiatus grows abun- 

 dantly on plastered walls, either bare or whitewashed, where 

 the minute quantity of size is evidently no element in the 

 question, and we have seen C. disseminatus in a similar 

 situation producing most abimdant mycelium, and that on 

 stuccoed walls void of all organic matter. Instances also 

 might be brought forward of three or more species of Peziza, 

 and those of considerable size, which flourish in such positions; 

 Chcetomium datum occupies not imfrequently the same 

 locality as does Lycogala parietinunfi, and the list might 

 easily be increased. Nor in these cases is there any subjacent 

 wood, from which the mycelium might spring, and thus, after 

 penetrating the coat of lime, produce its fruit in the free air. 

 In the cases of Chcvtomium and Licea, we have Fungi pecu- 

 liarly indifferent to the substances on which they grow, and it 

 is possible, therefore, that they may belong, more properly, to 

 the first exceptional case. 



228. A third exception to the most salient character of 

 Fungi, is that several species either grow on living animals or 

 on animal substances. Botrytis Bassiana is a familiar instance, 

 which produces the disease in silkworms called muscardine.* 



* Other caterpillars are freqiiently as completely mummified. It is 



