TILLETIA TRITICI 



235 



taper to a point, (3) whilst still attached to the promycelium they 

 may give rise directly to basidiospores, and (4) they are never shot 

 away and do not serve to disseminate the fungus. In all these 

 characteristics the primary conidia of Tilletia tritici resemble the 

 sterigmata of the Hymenomycetes. 



Further evidence, and evidence of a weighty kind, supporting 

 the view that the sickle-shaped 

 so-called secondary conidia are 

 the true basidiospores and that 

 the structures which support them 

 are not in reality primary conidia 

 but sterigmata is furnished by the 

 comparative morphology of the 

 basidial apparatus in the Tilleti- 

 aceae in general. Let us consider 

 seriatim the basidial apparatus 

 of (1) Urocystis violae, (2) Tuber- 

 cinia trientalis, (3) Tilletia tritici, 

 and (4) Neovossia moliniae. ( 1 ) In 

 Urocystis violae (Figs. 115 and 

 116) the fact that the primary 

 conidia and the secondary conidia 

 are in reality nothing but sterig- 

 mata and spores respectively 

 seems obvious from their shape 

 and appearance * and, involun- 

 tarily, the basidial apparatus of 



this species reminds one of the basidia of Tulasnella, one of the 

 Hymenomycetes. (2) In Tubercinia trientalis the primary conidia 

 look like fat sterigmata, but they conjugate basally in pairs whilst 

 still attached to the basidium-body. 2 As a result of conjugation, 

 a single secondary conidium is produced terminally on the end of 

 one of each pair of conjugated elements. Again the whole basidial 



1 O. Brefeld, Untersuchungen iiber Pilze, Miinster, Heft XII, 1895, Taf. XI, 

 Fig. 10. 



2 M. Woronin, " Beitrage zur Kenntniss der Ustilagineen," in de Bary and 

 Woronin's Beitrage zur Morph. a. Phys. der Pilze, No. 5, 1882, Taf. Ill, Figs. 1-12. 



Fig. 115. — Swellings in the tissues 

 of Viola odorata caused by Uro- 

 cystis violae. After Dietel. From 

 Die naturlichen Pflanzenfamilien. 

 Natural size. 



