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OUTLINES OF BRITISH FUNGOLOGY.

pearance, and do not cease till we reach an altitude of 18,000feet.

In respect of genera, they are in general diffused almostindiscriminately over the surface of the globe. A few generaonly arc peculiar to warm climates, and some of these havetheir representatives on either side of the basin of the Medi-terranean. The same species occur sometimes at great dis-tances from each other, being confined to small districts ineach locality. Java, the Sikkim Himalayas, New Zealand,and South Carolina, produce a curious plant,* allied to Geaster,which occurs on decayed laurels, without any intermediatestations, and other instances might he brought forward. Thespecies which occur in different tropical countries often differwidely, especially the Polypori, hut it is certain that there arehundreds of undescribcd species to reward future researches,and till the genus has been more closely studied, it is difficultas yet to come to any accurate conclusions.

As regards cosmopolite species, it is curious that the com-mon Mushroom is one of the most universally diffused, butit may be doubted whether this has not accompanied the in-troduction of the horse, consequent on the dispersion of thehuman race.

But little has at present been made public respecting thedistribution of species in Europe. Fries is, however, collect-ing materials for the solution of this difficult question. Thegreat evil is, that so few persons have made such a critical »study of the more important species which retain their cha-racters but imperfectly when dried, that it is not alwayspossible to give implicit credit to lists of species which maybe published in local Floras. Indeed, some notion of thedifficulty may be found from the frequent alterations of sy-

* Trichoscytale paradoxa.