278 FUNGI. 



European states in the number of species of the Discomycctes. 

 The Phacidiacei are not confined to temperate regions, but are 

 more rare elsewhere. Cordierites and Acroscyphus (?) are tro- 

 pical genera, the former extending upwards far into the tem- 

 perate zone, as Hysterium and Rhytisma descend into the tropics. 

 Amongst the Sphceriacei, Xylaria and Hypoxylon are well repre- 

 sented in the tropics, such species as Xylaria Tiypoxylon and 

 Xylaria corniformis being widely diffused. In West Africa an 

 American species of Hypoxylon is amongst the very few speci- 

 mens that have ever reached us from the Congo, whilst 

 jBT. concentricum and Ustulina vulgaris seem to be almost cosmo- 

 politan. Torrubia and Nectria extend into the tropics, but are 

 more plentiful in temperate and sub- tropical countries. Dothidea 

 is well represented in the tropics, whilst of the species of 

 Sph&ria proper, only the more prominent have probably been 

 secured by collectors ; hence the Superficiales section is better 

 represented than the Obtectcz, and the tropical representatives 

 of foliicolous species are but few. Asterina, Hicropeltis, and 

 Pempliidium are more sub-tropical than temperate forms. The 

 Perisporiacei are represented almost everywhere; although 

 species of Erysiphe are confined to temperate regions, the genus 

 Meliola occupies its place in warmer climes. Finally, the 

 Tuleraceij which are subterranean in their habits, are limited 

 in distribution, being confined to the temperate zone, never 

 extending far into the cold, and but poorly represented out of 

 Europe. One species of Mylitta occurs in Australia, another 

 in China, and another in the Neilgherries of India ; the genus 

 Paurocotylis is found in New Zealand and Ceylon. It is said 

 that a species of Tuber is found in Himalayan regions, but in 

 the United States, as well as in Northern Europe, the Tuber acel 

 are rare. 



The imperfect condition of our information concerning very 

 many countries, even of those partially explored, must render 

 any estimate or comparison of the floras of those countries most 

 fragmentary and imperfect. Recently, the mycology of our own 

 islands has been more closely investigated, and the result of 

 many years' application on the part of a few individuals has 



