IRREGULAR NUTRITION' 



229 



closely investing the superficial cells of the root, and forcing them 

 apart ; but still they appear healthy and active. The fungal fila- 

 ments do not as a rule pene- 

 trate the cells themselves, so 

 that the investment is morpho- 

 logically external. It is, how- 

 ever, so complete when fully 

 developed that the surface of 

 the root has no direct contact 

 with the soil, and must take its 

 supplies through the medium 

 of the fungus. The hyphae at 

 the outer surface grow out into 

 absorptive filaments that take 

 the place of the root-hairs. In 

 this particular type the root- 

 cap is shed off in layers, which 

 are held in the fungal mantle. 

 Like the native Monotropa 

 (Bird's Nest) growing in Fir 

 and Beech woods, and develop- 

 ing ectotrophic mycorrhiza, 

 Sarcodes is a complete sapro- 

 phyte and shows, as with the 

 complete parasites, a reduced 

 vegetative system including an 

 almost complete lack of chloro- 

 phyll (Fig. 157). The only 

 visible source of nutrition of 

 these plants is from the abund- 

 ant decaying vegetable matter 

 (humus) of the woodland soils 

 in which they live, presumably 

 through the intermediary of the 

 fungus. These higher plants 

 would thus appear to be sapro- 

 phytes at second-hand. 



The toadstools of various 

 types which are commonly 



found in WOOds are the Spore- shoot,' with' broad sheathing scales below, and a ter- 



minal inflorescence with prominent bracts. Reduced 



bearing parts of fungi which (After Oliver.) 



Fig. 157. 

 Whole plant of Sarcodes, showing the mycorrhizic 

 root-system, from which arises a bulky flesh-coloured 



