Distribution of Fungi. 285 ~ 
After these general observations, we will now proceed with a 
more detailed exposition of the geographical distribution of the 
principal genera of Hymenomycetes and Gastcromycetes, with 
respect to which it is often very difficult to decide whether their 
centre is in the tropical or the temperate zone. 
Ti. 
The most important family in the immense class of Fungi is 
without question that of the Hymenomycetes, which far excel 
all other Fungi both by the richness of their organization and 
the beauty of their forms. We have already mentioned the 
principal distinction which prevails extensively between the Hy- 
menomycetes of the south and those of the north, the fleshy 
species predominating in the colder and the ligneous in the hot 
zone. Another circumstance to be noted, on making a compari- 
son of the Hymenomycetes pileati of Europe with those of coun- 
tries out of Europe, is, that while the differences obtaining be- 
tween the specific types is considerable, there are few or none to 
be found between the several tribes ; and further, the genera are 
always the same. 
The genus Agaricus occupies the first rank among the Agari- 
cine, and surpasses in the number of its species all the other 
generic groups known. In the present state of our knowledge, 
it appears to be well established that the Agarici have their 
geographic centre in the temperate zone, and especially in the 
colder portion of that zone, as though nature had destined them 
in those regions for the nourishment of their inhabitants ; in 
fact, they largely serve this purpose in many countries, such as 
Hungary, Russia, and in general all the Slavonic territories. 
In Sweden alone, from the domination of vulgar prejudices, are 
their useful purposes overlooked and ignored. It 1s a curious 
circumstance that all the extra-European species of this genus 
Agaricus may be referred to various Kuropean subgenera. 
In tropical countries it appears that the Agarict occupy only 
a secondary position in relation to other genera of Fungi, such 
as Polyporus, Lenzites, &e. North America, on the other hand, 
is richer in species of Agaricus than Kurope; for, whilst the 
majority of typical forms are common to both continents, Ame- 
rica further possesses many species peculiar to itself. In the 
temperate zone, so close is the analogy prevailing between the 
various countries in respect to the Agaricine, that from Sweden 
to Italy, and as well in England as in North America, the same 
species are to be found. Of five hundred Agaricine met with in 
St. Petersburg, there are only two or three which have not been 
discovered in Sweden; and again, of fifty species known in 
Greenland, there is not one that is not common in Sweden. 
