270 SUMMARY OF CURRENT RESEARCHES RELATING TO 



and had noted the influence exercised by changes in the nutritive condi- 

 tion of the substratum, the evolution of each conidium, whether free or 

 anastomosed, and the absence of any direct advantage in the sexual 

 process. In water, whether rain, spring, or distilled, the phenomena of 

 fusion were never observed. In decoction of Carex leaves, and in other 

 nutritive solutions, the fusion was observed, the less rapidly the more 

 nutritive the fluid. Three types of union were noted : apposition by the 

 apices, apposition at an angle, apposition in H-form. In the fusion of 

 the conidia of Tolyposporium an essential condition is the progressive 

 diminution of the nutritive capacity of the substratum. 



Passing to a review of the phenomena of fusion in Ustilagineae 

 generally, the author notes two forms in which it occurs in water — 

 («) fusion of spores, (b) fusion of the points of the germinal tube of the 

 spores. In the latter case (1) two segments of the same tube may be 

 apposed ; or (2) two segments of the same filament, separated by one or 

 more points, may unite ; or (3) two segments of distinct tubes may come 

 together. After discussing these, Sig. Morini describes the germination 

 of the spores in a nutritive solution. In Tilletia sp., and in Enfyloma the 

 spores do not germinate ; in a second series ( TJ. Maydis, TJ. Vaillantii, &c.) 

 they pass through the usual saprophytic phases, and the conidia remain 

 always free ; in TJ. Betonicse, TJ. longissima, and Tolyposjjorium cocconii 

 fusion is observed when the nutritive medium begins to be exhausted. 

 After discussing these facts, and corroborating his previously expressed 

 opinion, the author emphasizes that those who would insist on sexuality 

 have to explain an extraordinary complication of apogamy, partheno- 

 genesis, isogamy, incipient heterogamy, and useless sterile sexuality. 

 He gives other reasons for maintaining that the fusion of conidia in 

 Ustilaginese is an asexual conjugation. 



Germination of the Spores in Ustilag-o.* — Following up his pre- 

 vious researches, Sig. F. Morini has made a special study of the germi- 

 nation of the spores in TJstilago Vaillantii. His general conclusions are 

 as follows : — (1) In spring water, filaments are formed, more or less 

 long, generally somewhat branched ; each spore usually germinates from 

 two opposite points ; (2) in rain water, the direct formation of filaments 

 is much more reduced ; short tubes are formed, but not abundantly, and 

 these finally give rise to short filaments ; (3) in nutritive solutions, the 

 spores form simple tubes, frequently forming a short branch, which 

 reproduce by budding ; when the medium begins to be exhausted longer 

 filaments are formed, more frequently branched, and separating off 

 terminal portions as ovoid cells ; these new elements, somewhat like 

 conidia, occur only on a restricted number of filaments, and have no 

 special disposition on the hypha ; (4) finally, when the nutritive medium 

 is exhausted, a double formative activity is exhibited, destined to pre- 

 serve the fungus in a latent state ; on the one hand, there is a formation 

 analogous to t;he chlamydospores of Mucorini ; on the other hand, a 

 process similar to the budding prolification of the spores and of the 

 mycelial tubes of some Mucorini, and to the gemmiferous segmentation 

 of some micronematous Hyphomycetes. 



Tremella fimetaria.t — M. E. Boudier states that since Schumacher 

 in 1881 described Tremella fimetaria, this species has not been found 



* Mem. Accad. Sci. Bologna, vi. (1886) pp. 689-94 (1 pi.). 

 t Morot's Jouni. Bot, i. (1887) pp. 330-3. 



