THIELAVIOPSIS PARADOXA. 523 



The microconidiophores were about 100 ^ji long and of 

 varying diameter according to the part measured, being 

 widest (8-10 [x) considerably behind the middle, and thence 

 tapering to the open end. His figures represent them as 

 terminal, not lateral. The microconidia were produced 

 within the hyp ha, and were cylindrical, nearly colourless, 

 10-14 X 5 ^, in numbers up to twenty, but generally less 

 than ten. Sometimes they were smaller, ellipsoidal, with a 

 thicker and darker wall. 



The macroconidia are said to be borne in an entirely different 

 manner, in chains at the ends of special branches. They were 

 more or less ellipsoidal, brown or blackish, and measured 

 16-19 X 10-12 jx. 



Cobb states that the microconidia germinate readily, merely 

 in the presence of moisture, but that the macroconidia require 

 a period of rest before germination. The latter observation is 

 incorrect. Contrary to the case of coconut, and the experience 

 of the workers with sugar cane, Cobb states that both micro- 

 and macro-conidia are formed within the tissues of the pine- 

 apple. 



He describes (15) another form of microconidium which 

 occurred on the cut surface of diseased pineapple shortly after 

 cutting. These were formed in the usual way, within the 

 tube, but were united in moniliform chains as "in the case of 

 the aerial conidia of Spkcerotheca pannosa and other Erisy- 

 phacece." His figure resembles a chain of conidia of Cystopus. 

 (Nothing of this kind has been observed by other investigators ; 

 the conidia first formed on the cut surface of diseased tissues 

 are normal microconidia, which may adhere in chains but are 

 united.) 



In the germination of the microconidia, the spore is said to 

 become nearly spherical. 



Lewton Brain. 



Lewton Brain (16) working in Hawaii claims to have 

 obtained Thielaviopsis spores by sowing Melanconium spores 

 in culture media. He writes : " The evidence for the view that 

 Thielaviopsis and Melanconium are different stages of one and 

 the same figure is, briefly, that when we sow Melanconium 



