578 A TEXTBOOK OF BOTANY [On. XIV 



through half -parasites ; these are really epiphytes sending 

 haustorial roots into the hosts, and absorbing organic food 

 instead of water and mineral salts only. The transition is 

 illustrated within the order Santalales (page 543). Most of 

 the hysterophytes, however, are Fungi, fully described in the 

 preceding pages. No essential physiological differences exist 

 between saprophytes and parasites, which moreover are alike 

 in their forms, and hence may be treated together. The 

 principal vegetation forms are the following. 



EPIPHYTIC PARASITES; Spermatophytes, really epiphytes 

 without chlorophyll, and hence with reduced leaves and 

 stems, sending haustorial roots into the tissues of the host, 

 whence they draw organic food ; typified by the remarkable 

 Rafflesia (Fig. 61), and by many members of the Loranthaceae 

 (Fig. 543). Allied is the form of the Dodder (Fig. 59). 

 TOADSTOOL HYSTEROPHYTES ; a wide-ranging, fine-branching 

 mycelium in host or substratum, producing a large sporophore 

 exposed to the winds (Fig. 328), as typified by the Toadstools, 

 Bracket Fungi, etc., both parasites and saprophytes, of the 

 Ascomycetes or Basidiomycetes. HETERCBCIOUS PARA- 

 SITES ; having stages with parasitic mycelium on more than 

 one host, bearing distinctive spore bodies on the surface of 

 each ; typified by Smuts, Rusts, and other Fungi. HYDRO 

 PHYTIC PARASITES, living in water upon insects, with limited 

 mycelium, typified by Saprolegnia (Fig. 302). ENDOPHYTIC 

 HYSTEROPHYTES; typified by many Bacteria and Yeasts, 

 living in solutions, with spores set free by the desiccation or 

 decay of the substratum. FREE-MOVING SAPROPHYTES; 

 typified by the Myxomycetes, with motile plasmodium. 

 MYCORHIZA; symbiotic association of a fungus mycelium 

 with the root tips of the higher plants (page 244, Fig. 172). 



E. THE PECULIAR HABIT OF THE INSECTIVOROUS PLANTS. 



A peculiar form of parasitism is found in the insectivorous 



Jiabit, Certain plants are known to catch insects, digest 



the bodies, and absorb the products, thus supplementing 



