260 ABSORBING SYSTEM. 



plant-body as a whole. As was pointed out at the beginning of this 

 chapter, the richly branched filamentous mycelium of the Fungi, in 

 fact, represents an enormously developed system of absorbing organs. 

 Where the mycelium takes the form of more or less bulky strands 

 (rhizomorphs) as in the Phalloideae and in many Lycoperdaceae, 

 Agaricineae, etc., the latter put forth special hair-like hyphae, which 

 project from the surface and perform the office of absorption, being, in 

 fact, directly comparable to the root-hairs of Higher Plants. 



Among Lichens the lower side of the thallus produces numbers of 

 rhizoidal hyphae, which likewise act as root-hairs. In certain species 

 they are united to form stout strands, the so-called rhizines. 



Many parasitic Fungi, such as the Peronosporeae, Uredineae 

 and Erysiphales, absorb their food-materials with the aid of 

 haustoria, which penetrate into the interior of the host-cells. In its 

 simplest form such a haustorium consists of a vesicle of varying size 

 joined to the parent hyphae by a slender stalk, which traverses 

 the wall of the host-cell (certain Erysiphales, Cystopus candidus, 

 Fig. 105 a). The more elaborate types of haustoria are usually 

 branched or lobed, and thus expose a far greater absorbing surface 

 (Erysiphc gra minis, Peronospora parasitica, P. calotheca, Fig. 105 b); 

 mention may also be made of the tufts of exceedingly delicate hyphae, 

 which represent the haustorial organs in Piptoccphalis frescniana and 

 other small Mucorineae that are parasitic upon the larger members of 

 the same family. 



