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RESEARCHES ON FUNGI 



Fig. 108. — Tilletia tritici. Diagram of a 

 basidium showing several primary 

 basidiospores (Brefeld's secondary 

 conidia) developing simultaneously 

 and their mode of discharge. In the 

 description the authors' terminology 

 will be employed and the Brefeldian 

 terminology added in brackets : a, 

 the substratum ; b, a chlamydospore 

 which has germinated ; c, the basidium- 

 body (promycelium) ; d, twelve primary 

 sterigmata (primary conidia) which 

 have conjugated in pairs. Each pair 

 of conjugated primary sterigmata has 

 produced a short tapering secondary 

 sterigma (sterigma) e e , bearing a sickle - 

 shaped primary basidiospore (second- 

 ary conidium)/, g. Above e-/is a very 

 rudimentary primary basidiospore 

 (secondary conidium) which is globular 

 and seated symmetrically on its ste- 

 rigma ; /, a ripe primary basidiospore 

 (secondary conidium), asymmetrically 

 seated on its sterigma ; g, a primary 

 basidiospore (secondary conidium) 

 which has just excreted a drop of 

 liquid at its hilum and is about to be 

 discharged ; h, a primary basidiospore 

 (secondary conidium) which, along 

 with its drop, has just been shot away 

 from a sterigma at the back of the 

 basidium. Magnification, 666. 



is rarely, if ever, to be seen 

 on the tuft at any particular 

 moment. 



(2) Just as in (1), the pairs 

 of primary conidia remain 

 seated on the promycelium and 

 each pair puts out laterally a 

 short sterigma (/in Fig. 109, A) 

 upon the end of which there 

 develops a single secondary 

 conidium (g and h) ; but, un- 

 like what happens in (1), the 

 secondary conidia are not dis- 

 charged and each of them puts 

 out a germ -tube into the air (i). 

 As a germ -tube grows in length, 

 the H -shaped pair of primary 

 conidia, together with its ste- 

 rigma, the secondary conidium, 

 and the germ-tube, may fall 

 away from the promycelium. 

 If the germ -tube then happens 

 to come into contact with a 

 nutrient medium, such as nialt- 

 agar, it may develop into a 

 mycelium which later may 

 produce numerous secondary 

 conidia. The mode of develop- 

 ment just described and illus- 

 trated in Fig. 109, A, must be 

 considered as abnormal for it 

 occurs under unfavourable con- 

 ditions (closed chamber, excess 

 moisture). It is doubtless 

 correlated with a failure in 

 the drop-excretion discharge 

 mechanism : each secondary 



