GROUP I. THALLOPHYTA : FUXGI. 275 



is set free as a somewhat spherical unciliated cell destitute of a 

 cell- wall, and germinates without any quiescent period. 



The germination of the tetraspores and of- the carpospores has 

 only been followed in a few cases. Generally speaking the spore 

 becomes elongated in form, and is attached by the more pointed 

 end which is almost colourless ; division by a transverse wall then 

 takes place ; the elongated attached cell developes into the root, 

 the other into the shoot. 



The Rhodophyceae are almost exclusively marine ; the only 

 fresh-water forms are Batrachospermum, Lemanea, and species of 

 Chantransia, Bangia, and Hildenbrandtia. 



CLASS II.-FUNGI. 



This class, like the preceding, includes many very simple 

 organisms, as well as others of tolerably high development. None 

 of them contain chlorophyll ; hence they cannot assimilate so 

 simple a carbon-compound as carbon dioxide, but must take up 

 their carbonaceous food in the form of rather complex compounds, 

 and their structure and mode of life are correlated with this 

 peculiarity (see p. 189). Some are parasites, such as the Rusts and 

 Smuts, and absorb these complex carbon-compounds from other liv- 

 ing organisms, whether plants or animals. Others are saprophytes, 

 absorbing these compounds from the remains of dead organisms, 

 or from organic substance formed by living organisms ; the numer- 

 ous and often large Fungi which grow on humus or leaf-soil in 

 forests, or on the bark of trees, are examples of the former case ; 

 the Yeasts and Moulds which make their appearance on juicy 

 fruits, saccharine liquids, etc., are examples of the latter. Some 

 Fungi are symbiotic ; that is, they live in intimate relation 

 (symbiosis) with plants which possess chlorophyll, and obtain 

 from them the necessary carbonaceous food, but without destroy- 

 ing, or apparently injuring them. They commonly live with 

 Algae, forming Lichens ; or in connexion with the roots of trees 

 (esp. Cupuliferae) and of Orchids, Leguminosae, and other plants, 

 or with prothallia (e.g. Lycopodium), forming what is known as 

 Mycorhiza. 



The vegetative body may be unicellular, or coenocytic. In the 

 former case it is small and rounded or rod-shaped in form. In 

 the latter case the body is always a mycelium, consisting of more 

 or less branched filaments, termed hyphce. The mycelium may be 



