TILLETIA TRITICI 



219 



Fig. 107. — Tilletia tritici. The germination of the chlamyriospore, the formation of 

 the promycelium (later interpreted as the basidium-body), and the production 

 of primary conidia (later interpreted as primary sterigmata) and secondary 

 conidia (later interpreted as basidiospores) on malt-agar. A, a mature chlamy- 

 dospore showing its sculptured outer wall. B, a chlamydospore that has just 

 emitted a germ-tube. C, a chlamydospore with a germ-tube which has become 

 divided into two cells, a dead basal cell and an apical cell filled with protoplasm. 

 D, a chlamydospore with an abnormal germ-tube ; the germ-tube has put out 

 a lateral branch into which the protoplasm is passing ; the empty parts of the 

 germ-tube have become septate and consist of dead cells. 



E, a chlamydospore with a normal germ-tube ; the germ-tube has become the 

 promycelium (basidium-bcdy) and it consists of two empty basal cells b and an 

 apical cell a filled with protoplasm ; the apical cell a has developed twelve 

 primary conidia (primary sterigmata) p, of which, for the sake of simplicity, 

 only the front six are shown ; the primary conidia, as yet, have attained only 

 about one-third of their ultimate length. 



F, a mature basidium. The chlamydospore c has germinated on malt-ajar 

 and has produced a promycelium (basidium-body) consisting of three basal 

 cells b which have lost their protoplasmic contents and are dead, and of an 

 apical cell a which is lined with cytoplasm and is living. The promycelium 

 may be supposed to hav6 been crowned by twelve long and slender primary 

 conidia (primary sterigmata) p p which have conjugated in pairs ; but, for the 

 sake of clarity, only the front three pairs have been represented. The proto- 

 plasm migrated from the promycelium into the primary conidia and, during 

 the migration, the promycelium developed three septa in succession from its 

 base to its apex. The right and left pairs of primary conidia have each pro- 

 duced a short sterigma (seoondary sterigma) st and a secondary conidium 

 (primary basidiospore) s. The protoplasm in the pair of primary conidia on 

 the right migrated into the secondary conidium s and, during the migration, 

 the primary conidia became exhausted and septate. In the pair of primary 

 conidia on the left the migration of the protoplasm into the secondary conidium 

 is nearly but not quite completed. The middle pair of primary conidia has 

 only recently conjugated and has not yet produced a sterigma and a secondary 

 conidium. Hence it is full of protoplasm and not yet septate. Within an hour 

 the secondary conidium s on the right would be shot violently away from its 

 sterigma. Magnification, 660. 



