Germination of Teleutospores of Ustilaginee. 87 
known since 1807, when Prevost* figured not only the 
promycelium, but the primary and secondary promycelial 
spores. Mr, Berkeley,f in 1847, discovered the conjugation 
of the primary spores, which was again more fully investi- 
gated by Tulasne.{ Kiihn§ gives a full account of the 
process. Since then nothing has been added to our know- 
ledge of the subject, till Wolff || showed the method by 
which the germ-tube enters the host-plant, and Brefeld J 
investigated the further development of the spores in 
nahrlésung. 
The spores do not germinate until they have been 
placed in water for some considerable time, not before 
forty-eight or fifty hours ; but often I have found them to 
take a much longer period. They retain their germinative 
power for two or three years, and one author says as long 
as eight and a half years.** The process differs materially 
from that previously described in the other genera. The 
promycelial tube is emitted from a small germ-pore, but 
very soon, as the tube increases in diameter, it causes the 
epispore to split. Its length varies according to circum- 
stances, its diameter being about 8u. If it be given out 
from a spore under water, at the bottom of the culture-drop, 
it grows upwards until its apex reaches the air. As soon 
as the promycelium has reached the air several tubercula- 
tions appear upon its‘ssummit. The protoplasmic contents 
of the spore are passed along the promycelium to its 
extremity. If the promycelium happen to be a very long 
one, then numerous septa occur from below upwards ; but, 
* Prevost, ‘* Mémoire sur la cause immédiate de la Carie.” 1807. 
+ Berkeley, ‘‘ Propag. of Bunt,” Zrans. Koy. Hort. Soc. (1847), *vol. ii. 
p. 113. 
t Tulasne, “1° Mém. sur les Ured. et les Ustilag.” 1854. 
§ Kiihn, ‘‘ Krank. der Kulturgew.” 1859. 
\| Wolff, ‘Der Brand des Getreides.” 1874. 
 Brefeld, Joc. cit., pp. 146-163, t. xii., xiii. figs. 25- oe 
** Liebenburg, Joc. cit. 
