164 



A NEW AND PARASITIC 



sections of the lam 



tissues. 



I 



such sections the whole depth of the green 



ypod 



tissue is seen to be permeated by enormous mycelial tubes (Plate VIII 



Figs 



12-17) 



The larger 



of these run more or less parallel with the length of the 



axis and are crowded with vacuolate, 



ely gr, 



colourless or pale ochreous 



protoplasm 

 numerous 



processes < 



biting very active 



streaming 



movements 



The 



largest 



tubes give off 



cwhat fi 



branches which are provided with flattened haustorial 



pplied t 



the outer surfaces of 



ghbourina; 



cells (PI 



Fig 



12b 



14, 



6 



I [ere and th 



branches pass off obliquely toward 



VIII, 



s the 



epidermis, and, when they reach substomatic spaces 

 One or sometimes two processes are jjiven off from 



j 



d 



and completely fill these 



this swelling and force their 



way 



n 



h tho stomatic orifice to form secondary dilatations beyond it, and from these 



the f 



filaments are in their turn g 



off (Plate VIII 



> 



Fig 



12« 



'f 



13) 



The 



hat dilated terminally so as to f 



capitulum 



d from this a 



of conidiiferous capitella corresponding to those of Choanephora Cunningh 



are 



given off 



In detail, ho 



tho characters of the capitella are very dist 



the two 



species 



When mature the capitella of 



here dealt with are abruptly truncate 



an( 



1 



mble the conidiiferous cells of BotrytU cinerea Pers., rather than the rounded capi 



tella of Choancph 



Cunningh 



M 



wh 



the conidia become detached th 



capitella never form the beautiful funnels from which the genus deriv 

 is no doubt owing to the 



name, wh 



> 



original diffe 



in their form and 



appreciable differences in the thickness of 



to the absence of any 

 walls over their lateral and terminal sur- 



i 



Tho number of capitella present in different instances varies considerably, but 



in 



many cases may 

 >hort ster 



The 



LT 



ach of which gives 



extremity beco 



covered with 



origin 



to a 



d 



The conidia when matur 



are 



ery 



decid 



harmana do, this being partially 

 cultures in nutritive inf 



1 fall off much more readily than those of Choanephora Gunning 



doubt, owinj to the abse 



of funuel 



In artificial 



the 



d 



appearan 





d when it does 



fructification comparatively rarely makes its 



feebly developed 



The 



pitula are 



and the 



capitella few in number, or they may both be completely suppressed and the steri" 



directly from the stem in more or less peronosporoid fashion (Plate IX, Fig. 10). 



The conidia when mature hav 



dimensiens of : 016x0'00S 



m 



They 



are 



fusiform in outline and are provided with a finely longitudinally striate epispore, differ 



mg 



thus both in f 



and structure from th 



( Plate IX, Fi 



17, 18) 



conidia of Ghoaneph 



Cunningh 



plant 



This conidial fructification is the only one which I ha 



ever 



as a 



par 



on Ip 



rubro 



may be produced within the tissues when external cond 



but probably 



fav 



duction of con id 



Under favourable conditions, however, 



mycelium produces conidial fructifieati 



during 



gospores 

 ;he pro- 



alon 



e 



i 



parasitic existence 



say, it only prod 



that form of fructificatioi 



in enormous profusion 



that 



is 



i 



Cann 



and vegetative growth. Both in 



which is associated 



th 



the result of 



regard 



conditions 



shall 



to this species and to Choanephora 



ficial cultures appears conclusively to show that nutri- 



the main factors determining the particular form which the fructifi- 



assume in individual instances. 



present purely 



vegetative 



growth 



Where very abundant nutritive 



occurs ; 



short of this conid 



fructification mak 



appearance; with greater diminution of supply the sporangial and zygosporic fructificat 



tend to annftfir: and. finally in +««. majMu ~£ _• • 1 .... 



IS 



its 



to appear; and, finally, in the presence of minimal 



are produced 



mydospores 



























