236 



RESEARCHES ON FUNGI 



apparatus when fully developed looks like a basidium of a Hymeno- 

 mycete, but one into which conjugation of the sterigmata has been 

 introduced. (3) We now come to Tilletia tritici. Here the basidial 

 apparatus, as compared with that of Tubercinia trientalis, has under- 

 gone a considerable degree of further modification. The primary 



conidia (sterigmata) 

 have become greatly 

 elongated, conjugation 

 takes place usually 

 about the middle of 

 the primary conidia, 

 and each secondary 

 conidium (basidiospore) 

 arises not on the end 

 of a primary conidium 

 (sterigma) as in Tuber- 

 cinia trientalis, but on 

 a lateral branch (second- 

 ary sterigma) of one of 

 the two paired primary 

 conidia. (4) Finally, in 

 Neovossia moliniae, the 

 primary conidia (sterig- 

 mata), while rod-like 

 like those of Tilletia 

 tritici, do not, so far as 

 is known, conjugate 



Fig. 116. — Urocystis violae. A spore-ball germi- 

 nating in water. Each spore is producing 

 what the authors interpret as a basidium con- 

 sisting of (1) a cylindrical basidium-body, 

 (2) a group of sterigmata swollen at their bases , 

 and (3) a single basidiospore terminating each 

 sterigma. After Brefeld. From Die natiir- 

 lichen Pflanzenfamilien. Magnification, 350. 



with one another, and 

 they are increased in number to over fifty on each basidium. When 

 these stick-like primary conidia germinate, they each give off a 

 lateral branch (secondary sterigma) on the end of which, as in 

 Tilletia tritici, there develops a sickle-shaped secondary conidium 

 (basidiospore) which doubtless is shot into the air by means of the 

 drop-excretion mechanism. 1 In the basidial apparatus of the 

 species of Urocystis, Tubercinia, Tilletia, and Neovossia which 

 have been considered we seem to have a progressive series leading 



1 0. Brefeld, loc. cit., Taf. X, Figs. 8-21. 



