AKTICULATIOX OF THK TIIALLL'S. , 



the other, ov organ of fructification. devolvL.^ tho tiisk of ..-,„., 

 diiftiou, and therefore the luuiiiteimme of the species Thih 

 hitter or^nin develoj.s spt^cial cells or spores, which are mostly 

 giol.ular or oval, and from each of which under favourabl'e 

 circumstances, u new individual of the s^ime species cuu be 

 proihiced. 



The myrelium may thertfurt.- he dctined as the jwrtion of the 

 thall us spreading; m or upon the nutrient medium and extractiui; 

 nuti-iment therefrou). It proceeds from a spore. As so<m ,»s 

 this latter couHvs un-ler tlu- intluence of circumstances favourable 

 to Its termination, it absorbs water and other nutrient materials 

 tro.u the surroun.lin-s, sw,-Ils up more or less, and usmilly puts 

 forth one or m.ne tubular buds (Fior. 92). These continue to 

 develop in two dirt-cticnis. incieasinf; in 

 length, and forming lateral branches which 

 in turn continue to act in like manner The ^2?^ 

 name hypha is given to each of these branch- ^; ■■' ^ 



ings, and tlje whole group of hiij>/i<,' that have ^ / 



resulte<l from a single spore and serve to 

 nourish the individual plant in question, is ^""^ 



called the myreliuiu. The spore mav also '^°-9* --^'"»^"'"niuc«do. 

 germinate by the process of gemmation .hirlr'aL.drpui 

 aescnbeU in ^ 219. In some fungi the spores '"rUi t«.. imdg. Magn. 

 can only germinate in the one manner, whilst '"" ^'^■""' ^'''"'^'^-^ 

 in others the germination is restricte.l to the other type The 

 mycelium, in order to fulfil its tisk, must cntinue to'peiietnite 

 towards more remote portions of the nutrient medium ; and 

 at-cor<lingly, the hyplue must pr..gressively increase in len.'th 

 ^ow this growth IS contined to the apex of the hvph:e, i.Ahe 

 part farthest from the centre of deveh.pment. On the other 

 hand the parts nearest that centre quicklv cease to extend and 

 branch ; consequently, the Kumf^rH.s exhibk acrogenous growth 

 llus behaviour constitutes another fe^iture of difference between 

 humyrete^ xxm\ Srhhonnjretes, since, in the latter, the growth of 

 the .-ells IS not restrict...! to one end onlv, but proceeds by the 

 extension of the whole body. 



Examination of the mycelia of a large number of species of 

 A«/«//'Wew, under a power of about 100 diameters, soon l«ids to 

 a separation of these sp.-cimens into two groups : the one com- 

 prising si)ec.es wh..se mycelium, however large and extensivelv 

 branched, consists of only one single cell; whilst the other 

 gr.nip contains thesj.ecies wherein the mvcelial hvpha> are sub- 

 .iivuh.,l mt.. cylindrical parts of variable h-ngth" bv tn.nsverse 

 walls (septa) perpendicular to the longitudinal axis. This fun- 

 damental an.l highly impo.t;int difference constitutes the chief 

 basis for the .separation of the Kiim,, ,-.(,, i„to two main .sub- 

 divisions: Kiimyretr, with a unicellular mycelium on the one 

 l>an.i. and Eiimyretes with a sept^iteil mvcelium on the other 



