248 THE VEGETABLE WORLD. 
nothing can exhibit greater extremes of development if the 
highest and lowest forms of Fungales are contrasted : the large 
fleshy Boletus, for example, which grows on the trunks of trees, 
and the microscopic mould-plant, composed of threads much too 
delicate to be distinguished by the naked eye, although the latter 
proves to be only a simpler form of the former. Viewed in their 
whole extent, the Fungales may be described as cellular flowerless 
plants, nourished through their thallus or mycellum ; having a con- 
centric mode of development ; living in the open air ; propagated 
by spores, colourless or brown, and sometimes enclosed in asci—that 
is, in transparent cells—and destitute of gonidia. ee’ 
The Fungales are very extensive as regards genera and species. 
The Rev. Mr. Berkeley gives the number as 598 genera and 4,000 
species, to which new forms are being constantly added. “In 
their simplest forms,” says Dr. Lindley, “ Fungales are little 
articulated filaments, composed of simple cellules placed end to 
end. Such is the mould found upon various substances—the 
mildew of the rose-bush, and all the tribes of Mucor and Mucedo. 
In some of these the joints disarticulate and appear to be capable 
of reproduction; in others, spores collect in the terminal joints, 
and are finally dispersed by the rupture of the cellule that contained 
them. In a higher state of composition they are masses of cellular 
tissue of a determinate figure, the whole centre of which consists 
of spores attached, often four together, to the cellular tissue, which 
at length dries up, leaving a seed-like mass, intermixed more oF 
less with flocci, as in the puff-balls, or sporidia contained in mem- 
braneous tubes or asci, like the theca of Lichens, as in the spheris. 
In their most perfect state they consist of two surfaces, one * 
which is even and imperforate, like the cortical layer of Lichen; 
the other, separated into plates or cells, and called the hymenium, 
to whose component cells, which form a stratum resembling the 
pile of velvet, the spores are attached by means of little processe> 
and generally in fours, though occasionally the number is more OF 
less.”” : 
Schleiden’s account of the reproductive process of F ungales " 
highly interesting. The most simple filamentous Fung}, the 
Hyphomycetes, form, “ at the end of the thread-like cells,” he Bay? 
-“ narrow protuberances, on each of which a spore is de eloped; 
