THALLOGENS. 7 



in the terrestrial Vaucherise, the terrestrial Sphserozyga, &lc., the fmit is 

 developed in free air ; so also in Botrydium, Trentepohlia, and some others. 



Mr. Berkeley finds that " the main distinction between Fungi and Algals 

 (Including Lichens) consists in the fact that Fimgi are universally nourished 

 by the matrix by means of their mycelium, while Lichens and Algals are 

 nourished at the expense of the medium in which they vegetate. In a few 

 cortical species of Lichens, indeed, there is a very intimate connection 

 between the bark and stroma, but then in these cases there are the green 

 gonidia which do not exist in Fungi. It is true that moulds will vegetate in 

 fluids ; but as soon as they assume their normal foim, there is a distinction 

 between the immerged and free portion." 



Following these views, I ventm-e to propose the following as the cha- 

 racteristic mark of the 



Alliances of Tiiallogens. 



Algales. — Cellular Jlowerless plants, nourished through their whole surface 

 hy the medium in which they vegetate ; living in water or very 

 damp places ; propagated by zoospores, coloured spores, or 

 tetraspores. 



Fungales. — Cellular Jlowerless plants, nourished through their thallus [spawn 

 or mycelium) ; living in air ; jjrojmgated by spores colourless 

 or brown, and sometimes inclosed in asci ; destitute of green 

 gonidia. 



Lichenales, — Cellular Jlowerless plants, nourished through their whole sur- 

 face by the medium in which they vegetate; living in air ; 

 jyrojmgated by spores iisually inclosed in asci, and always 

 having green gonidia in their thallus. 



