GEOGRAPHICAL DISTRIBUTION 325 



almost in the same position as they were. The southern 

 hemisphere exhibits some improvement, but this is principally 

 around old centres. In South America activity has been con- 

 fined chiefly to the eastern side, south of 20°, and for about 

 twenty degrees southward, but beyond that all is silence. The 

 hopes that the Dark Continent, which has evinced so much 

 vitality in other directions, would furnish good botanical 

 records have not been fulfilled, and even the temporary activity 

 at the Cape has subsided into stagnation. From our point of 

 view the whole of Africa is nearly as it was in 1874. The 

 colonies of Australia have, nevertheless, added much to our 

 knowledge, through the efforts of a few local botanists, and 

 acquired the distinction of possessing a combined Flora of their 

 own, for the Fungi of five of the colonies. Other islands of 

 the Pacific are much as they were, and for the rest of the 

 world we can recognise no alteration, except perhaps some 

 additions to our knowledge of parts of Northern Asia, and a 

 little more of Egypt. 



Even in our own country we are conscious that Fungi are 

 more erratic in their appearance and disappearance than 

 flowering plants, and even than other cryptogams. It is in 

 the experience of every one that a species, or even an entire 

 genus, which is common in one year becomes scarce in the 

 next ; or that a comparatively common species may gradually 

 become rare in certain localities, through a series of years, and 

 at length vanish altogether. General conditions of temperature, 

 or humidity, affect the appearance of fleshy Fungi much more 

 than it does that of any other plants, and sometimes it is im- 

 possible to account for the fluctuation. For instance, in 1893 

 there were generally more of the- common mushroom to be 

 found in England than in any period during the previous 

 thirty years, and yet all other Agarics were remarkably scarce. 



The fleshy Hymenomycetal Fungi, of which the mushroom 

 is the type, belong almost exclusively to temperate regions ; as 

 warmer countries are approached, they are only found at high 

 elevations, whilst their representatives near the sea level 

 belong to genera in which the substance is tough and leathery, 

 and the proportion of water in their composition is compara- 

 tively small. Hence we find that nearly all the Fungi of the 



