TILLETIA TRITICI 261 



Leonian agar, each basidiospore, as a rule, puts out a single germ- 

 tube only. The conditions of nutrition permit of the fungus living 

 saprophytically for a long time. The germ-tube develops into a 

 mycelium which branches and rebranches in a coiled manner and 

 eventually gives rise to numerous new basidiospores, as illustrated 

 in Fig. 130, C. Protoplasmic migration and the production of septa 

 eventually take place, and these phenomena are to a large extent 

 correlated with the transference of protoplasm into the new crop of 

 basidiospores. The mycelium developed during the first few days 

 is composed of very thin hyphae ; but, later on, thick irregular 

 hyphae are produced in addition. Both types of hyphae give rise 

 to basidiospores. When a basidiospore is shot away and falls on 

 to the agar, it sometimes at once gives rise to another basidiospore 

 which may be shot away (Fig. 130, B, a, b). Sometimes a chain of 

 three successive basidiospores is formed in this way ; but, in such 

 a case, the second basidiospore cannot have been shot away. 



Basidiospores were successfully germinated in a Petri dish on 

 sterile green-house soil, and the mycelium gave rise to new genera- 

 tions of basidiospores up to the fifteenth day after the original 



Fig. 130— cord. 



has directly produced a sterigma and is now developing a new basidiospore ; 

 c, an undischarged basidiospore, still seated on its sterigma, which at its 

 base has produced a new sterigma and a new spore. Magnification, 570. 

 C, a basidiospore (primary or secondary) a which has been shot from 

 its sterigma, has fallen on to fresh malt-agar, has germinated, and has 

 given rise to a fine branched winding mycelium m bearing numerous 

 new secondary basidiospores, b-f, which in turn will be violently dis- 

 charged from their sterigmata : the original basidiospore a and the 

 older parts of the mycelium are now septate, devoid of protoplasm, and 

 dead ; the younger parts of the mycelium h h still contain protoplasm 

 which is creeping towards the apices of terminal hyphae and into the 

 developing basidiospores and, basally, is forming new septa ; b, a 

 mature basidiospore with a drop of maximum size excreted from its hilum 

 and about to be discharged ; c and d, two full-grown and almost mature 

 basidiospores, a few minutes before drop-excretion and discharge ; e, a 

 full-grown basidiospore into which protoplasm is still flowing from the 

 mycelium ; /, a rudimentary basidiospore which at present is no more 

 than a tiny spherical body symmetrically seated on the end of its sterigma; 

 g, a sterigma, devoid of protoplasm, from which a basidiospore has been 

 violently shot away in the direction of the arrow. Magnification, 570. 



D, the production of chlamydospores in old malt-agar cultures. The 

 mycelium has become relatively thick, very irregular, and often monili- 

 form : ic, immature chlamydospores with slight reticulations on their 

 outer walls; c, chlamydospores which have developed at the ends of 

 branches and whose outer walls are distinctly reticulated ; d, a swollen 

 ovoid cell terminating a hypha ; nm, netted mycelium, some of the 

 hyphae h have lost their protoplasmic contents and their walls are 

 disintegrating. Magnification, G60. 



