THE VARIOUS GROUPS OF PLANTS 



45 



Fig. II. — Some Fungi. A, cells of Yeast (Saccharoinyces) budding actively 

 ( ; 960); B, Diagram of Mticor iniicedo, a common Mould, showing the mycelium 

 growing synimetrically from a central spore, and developing sporangia, successive 

 stages of which are marked a, b, c, ( ■ about 20); C, Puffballs (Lycoperdon sp.) 

 which ha\'e opened at the top (x -/o); D, Stereiuii ajfine ( ■: li); E, a Stinkhorn, 

 I thy phallus (x I); F, Morel {Morchella) ( < f); G, Auricularia ( < i); H, the 

 Deadly Amanita {Amanita phalloides), a Gill Fungus ( < j); I, Boletus, a stalked 



Pore Fungus ( ; |). 



the commonly chitinous cell-walls and the storage of food mainly 

 as glycogen. Their reproduction may be effected vegetatively by 

 separation and subsequent development of part of the mass of 

 filaments, and asexually by spores which are usually of very small 

 size and produced in enormous numbers (sometimes millions of 

 millions by a single fruiting body). In some of the simpler Fungi 

 these asexual spores are swimming zoospores ; usually, however, 

 they are non-motile and are enclosed in a more or less resistant 

 wall. Various sexual processes occur, usually involving the fusion 

 of unlike gametes, gametangia, or hyphae, and resulting in the 

 production of resting or airborne spores. The ' budding ' practised 

 by Yeasts is another effective mode of vegetative propagation {see 

 Fig. II, A, above ; the formation of spores internally is seen below). 

 Fungi find habitats for existence almost everywhere there are 

 either living organisms to parasitize or dead and decaying organic 

 materials to attack. Many are aquatic, including marine, and some 

 grow actively even in the absence of free oxygen. The other 

 familiar habitats are soils, dung, and various foods, fabrics, and 

 wooden or other structures, which Fungi frequently cause to rot. 

 Thus they occur throughout the world wherever life is possible 

 and they can find materials upon (or in) which to grow. Yet as 

 c 



