

SPKCIES OF OHOAKEPHOKA. 



167 



oospores are liable to mak 



thesporangiierous ones, and in any average cultivation 



their appearance in varying numbers Tho™ ; a ,u- ^ V*,.* •"" "* *""" v 



a l • , n 4U * ° uumoeis. lhere is nothing to indicate what is the .sscirial 



determinant of the appearance of zvo-o*nor : e fmrfifi Z c • . , . 



4 ., , ., . ™\ n l z y & 0s P0i-C fructification, for, in two en t vations conduct 



ed side by side in portions of one and the Mma • 1 ,. u 



i x- i , . . t,le sam9 »P0«nien of a medium, zygospores inav 



be 3ntirely absent m one and nlmnsf bn*; M i«, i . . " ' - 



-,. . ,., aIm0!>t entl i*ely replace sporangia n the other Wli 



-r • ,., v " LUlue 7 replace .sporangia in tbe other. When tho 



dium is a very dilute one obkmydwpore. alone are proceed (Hat, VIII 1> - 



The phenomena attending tre fferminatinn «# fi, rt ,.i i , i , -~ .' . 



. , T ° e fcwuunation ot tho chlamydospores dilters in dii 



instances. In 



mg 



of cases tliey give origin to a mycelium lik 



from the spores and comdm, but « „ lally {nrt-noe. no mvclmm is formed „, : tl 



germinal tube elongates directly 



u 



feroua filament (Plate IX. E 



When the nutritive medium U not excessively pom, t „ or „„„.„ „*_,,„' ,'„ ' , 



;iv In 



formed in he course of individual mycelial filaments, but, w |, ( .„ tll0 lml ,„ iv ,. , ,;,. 



of the medium full very low, each conidium or .pore only IV0 . origin t„ , ,,,,-le 



chlamydospore, and this in many cases is directly continuous with the parent Imdv - 

 forms a simple extension of the latter (Plate IX, Figfc 5 



d 



The zygospores vary considerably in structural details even within 



culture. In 



they are quite typically zvgo>poi 



Inch contribute to their formation being of equal value, alike in size and rieral 



tubes 



cncrai ap- 



pearance ! Plate VIII, Figs. 4, 5, 8); in others one of the conjugating element! is mnc h 

 larger than the other, the difference between them in certain cases becoming so ex- 

 cessive that in this respect the process comes to bo rather of an oosporic than a I 

 gosporic type (Plate VIII, Figs. 6, 7, 0, 10), an 1 in a few cases the spore appears to be 

 of a truly azygospoi ic diaraeter and the product of a single mycelial process nl\ 

 VIII, Fig. 11). In some instances the conjugating processes take origin from the 



same mycelial filament, in others from distinct ones, and 



whilst in some cases they re 



unaccompanied by any other peculiar processes, in others they are associated with vary- 

 ing numbers of short, often twisted processes (Plate VIII, Figs, o, 8), although tbe* 

 never are present in such numbers as to givo rise to the formation ot the complicated 

 Bclerotioid masses of tissue which are occasionally associated with the zygospores of 

 Choanvphora C imnin g hamiana . Another point of difference in the zygospores in the pre- 

 sent as compared with the latter species is that the oosporic separation of the content! 

 from the wall of the spore and their subsequent investment with a special memhrano 

 which is so frequent in Choane-phora Cunninghamiana (Plate IX, Figs. 21, 22) ne\«r 

 appears to occur here. 



rn 



The colour of the contents of the conjugating processes varies from different 

 shades of yellow to strong reddish, and not unfrequently, at a time when the contents 

 of one process have already been completely accumulated terminally .and separated by 

 the formation of a partition, those of the other are present throughout its entire course 



d continuous with those of the parent mycelial filament (Plato Wlll^ Fig. 7). r I 



mature zygospores are of a deep brown or almost black colour and have average diameters 

 of 0-057 m.m. They rarely contain any massive accumulation of oil in the form of 

 a large globule, but, where such a body is present, it can be readily determined that 

 the epispore, like that of the sporangial spores and conidia, is finely striate 



VIII, Fig. 9). 



The germination of the zygospores has not yet been observed, but, judging from 

 the fact that the chlamydospores give direct origin to sporangic fructification whil>t 

 those of Choancphora Cunninahamiana produce a conidiai one, it appears probable that 

 they are the source of sporangia also. 







