BUNT OF WHEAT. 249 



If these spores are kept in moist air or on a wet surface 

 for three or four days, they will germinate, as at Fig. 116, 

 A, enlarged 1000 diameters. The epispore bursts, and a 

 thick septate tube is protruded. This tube, after it has 

 grown to three or four times the diameter of the spore, 

 forms a sort of small terminal crown, and on the minute 

 papillas of this crown it bears four, eight, or ten rocllike 

 sporidia, as shown at B. When these sporidia are fully 

 grown, and whilst still adherent to the apex of the germ- 

 tube, they coalesce, as at CO, by means of short transverse 

 tubes. When these conjugated bodies drop from the 

 supporting tube they germinate and produce secondary 

 sporidia of a different form, as shown at DD. At times 

 the supporting threads of these conidia are extremely long 

 and jointed throughout ; at other times there is no sup- 

 porting thread, but the conidium may grow from the end 

 of a secondary spore. Sometimes the sporidia are pro- 

 duced whilst the secondary spores are still attached to 

 their supporting stem. A spore or conidium so growing 

 is illustrated at G. The conidia, in turn, are capable of 

 germination and the production of conidia of the third 

 order, as at EE. Sometimes they so germinate without 

 the spores, DD, falling from their attachment. When 

 the secondary and tertiary sporidia, as at D and E, ger- 

 minate, they produce a septate thread of extreme tenuity, 

 as at F, and on this thread the bunt spores are at length 

 borne, as illustrated in Fig. 115. Sometimes bunt 

 spores do not produce, on germination, the minute crown- 

 like terminal cell, with its conjugating secondary spores ; 

 but the thick germ-tube grows for a great length, branch- 

 ing and rebranching, and all the time forming septa. 

 The vital material is chiefly confined to the terminal end 

 of each branch. When this mode of growth takes place, 

 conjugating spores are never formed. 



In some instances the secondary spores become con- 

 joined in two places instead of one, as illustrated by Mr. 

 Berkeley, and confirmed in two instances by Dr. Oscar 



