THIELAVIOPSIS PARADOXA. 513 



finds examples which have assumed the colour, and sometimes 

 the form, of the macroconidia. Further, when his cultivation 

 was old, he found that groups of erect sporophores were 

 produced, resembUng the stalks of an Isaria or Stysanus, 

 in which each microconidiophore retained its individuahty. 

 (This formation has not been recorded by any subsequent 

 investigators, though it is quite easily obtained.) 



F. A.F. C. Went. 



Went's first accounts of Thielaviopsis ethaceticus, and its 

 effect upon sugar cane, were published in agricultural jom-nals 

 which I have not been able to consult. The following de- 

 scription is taken from his article in the Annals of Botany (8). 



Went states that the conidia soon germinate in any nutrient 

 solution, and the cultures remain snowy wliite as long as only 

 vegetative mycehum is developed, but that in from twelve 

 to twenty-four hours they become olive-green or dark green, 

 owing to the formation of conidia. He was able to grow the 

 fungus on mangoes, pineapples, bananas, &c., and states that 

 it will grow on all sorts of materials containing sugar. (In my 

 experience, the change of colour takes place ajter the formation 

 of microconidia, when the macroconidia begin to appear.) 



The conidiophore which produces microconidia (de Seynes' 

 specialized conidiophore) is at first a thick, somewhat curved 

 branch of the mycehum, which lengthens into a regularly 

 tapering cell, 100-200 ^ in length, in which the conidia are 

 developed, and from which they are ejected in a continuous 

 chain. These microconidia are rectangular, and measure 

 10-15 X 3 • 5-5 \}.\ as a rule they are colourless ; but sometimes 

 they are shghtly coloured and more oval, thus resembling to 

 some extent the macroconidia. 



The macroconidia are situated in chains at the ends of short 

 branches of the mycehum : they are dark olive-green, and 

 measure 16-19 X 10-12 \x. The conidium at the top of the 

 chain is often almost spherical, but the remaining conidia 

 are more elongated. According to Went, the first macro- 

 conidium is formed by the growth of a septum across the 

 hypha, a short distance below the apex : soon afterwards a 

 second is produced by the growth of another septum below 



