262 RESEARCHES ON FUNGI 



basidiospores were sown. Attempts to obtain similar results on 

 unsterilised soil always failed. 



The Development of Chlamydospores in Culture Media. — 

 The development of chlamydospore-like bodies of Tilletia tritici on 

 artificial media has been observed by Brefeld, 1 Sartoris, 2 and others. 

 In the present investigation basidiospores were sown by the spore- 

 fall method on the surface of oatmeal-agar and Leonian agar in 

 Petri dishes, and the mycelium resulting therefrom was kept in 

 culture for some three months. Many of the hyphae grew along 

 the surface of the agar, others developed aerially, while others 

 penetrated below the surface of the agar to a depth of about • 2 mm. 

 A few weeks after the sowing of the basidiospores, the mycelial mat 

 began to turn yellow ; and, after 2-3 months, it was very brown 

 and, in some spots, almost black. 



A microscopic examination of the darkest patches of the mycelium 

 showed that they consisted of various types of hyphae and of 

 chlamydospore-like bodies (Fig. 130, D). Some of the hyphae were 

 thin and regular. Others were very thick and often moniliform, 

 and they frequently bore short, lateral, empty, septate branches 

 which terminated in dark, thick-walled, oil-containing, oval or 

 rounded, chlamydospore-like bodies. At the end of three months, 

 some of the dark bodies were spherical in shape and exhibited on 

 their dark outer wall the reticulations which are so characteristic 

 of the chlamydospores of Tilletia tritici formed in diseased grains of 

 wheat (Fig. 130, D, c). Very old cultures appeared to consist almost 

 entirely of large-celled chlamydospore-like bodies, most of the hyphae 

 having disintegrated and disappeared. Thus the life-history of 

 Tilletia tritici when grown on artificial media was followed in detail 

 from chlamydospore to chlamydospore and Brefeld's conclusion 

 that this parasite can be grown saprophytically was once more con- 

 firmed. Whether or not the chlamydospores developed on agar will 

 germinate and give rise to typical promycelia bearing sterigmata 

 and basidiospores has not yet been decided by experiment. 



1 O. Brefeld, Untersuchungen iiber Pilze, Heft V, 1883, pp. 158-163, Taf. XIII, 

 Figs. 47-52. 



2 G. B. Sartoris, " Studies in the Life History and Physiology of Certain Smuts," 

 Amer. Journ. Bot., Vol. XI, 1924, pp. 626-627. 



