8 



GENERAL MORPHOLOGY, 



fructification, and is then able to await and utilise the occurrence 

 of favourable conditions, in order to effect the reproduction of the 

 individual from which it has originated. An observation on the 

 artificial production of such permanent forms has been communi- 

 cated by J. Ray (I.). Among the foodstuffs accumvdated in the 



cells of the sclerotium, special im- 

 poi'tance attaches to glycogen (§ 253) 

 as the source of easily liberated 

 chemical energy and abundant dis- 

 engagement of heat. This substance 

 was first observed — without, how- 

 ever, being specially named — by 

 A. DE Bary (1.) in the sclerotium of 

 Ooprinus stercorarius ; and it was 

 afterwards found, by W. Rothert 

 (I.), in that of Sc/erofiuni hydro- 

 lihilum. A thin section of scler- 

 otium, or of a fungoid body — both 

 of which are, as already stated, com- 

 posed of a netwoi-k of hyphje — 

 exhibits under the microscope an 

 appearance similar to that of the 

 parenchyma of higher plants, e.g. 

 a section through the flesh of an 

 apple. On account of this similarity, 

 these networks of hyphae have re- 

 ceived the name 2^^^^doparenchyma, 

 which, however, is not intended to 

 express any further likeness, whether 

 in respect of the mode of forma- 

 FiG. 95.-Boletus eduiis. ^0^ or physiological purpose. It is 



Longitudinal section (above) and perhaps superfluous to emphasise 



transverse section (below) through ^\ ±. ^1,„ rnvppb'n nf thi<; flfl<5Q nf 



the fruit stem ("fungus") of Boletus ^^^i^ /^ne mjceiia 01 tnis ciass or 

 eduiis. Jiagu. 300. {After stras- fungi con.sist merely of hyphfe when 

 "^^^'^ in the earliest stages of existence 



and consequently at such times are indistinguishable in this 

 respect from the mycelia of the Hyphomijcetes. 



§ 219.— The Gemmating- Mycelium. 



The application of the name "typical" to a mycelium growing 

 in the manner described in the preceding paragraph, indicates 

 the possibility of other methods of growth, manifesting them- 

 selves as modifications and simplifications of this form. Of 

 these the most important, from our point of view, is the 

 gemmating mycelium, the development of which proceeds in the 

 following manner (Fig. 96) : The germ cell, or mother-cell, puts 

 forth a protrusion which, however, instead of enlarging to a tube 



