SYMBIOSIS 145 



where an infection patch occurs, from which hyphae 

 penetrate into the base of the scutellum of the embryo and 

 on to the growing point of the plumule, where a consider- 

 able patch of mycelium is formed which remains dormant 

 until germination takes place. On germination the hyphae 

 keep pace in their growth with the growing point, and can 

 be found there throughout the life of the plant. Hyphae 

 are present in all branches and leaf-bases. Their appear- 

 ance in the latter is considered to be due to similar 

 chemotactic properties in the basal leaf-meristem to those 

 present in the stem growing point. Hyphae develop 

 luxuriantly m the nucellus of the young ovaries, but do 

 not enter the embryo until the latter shows rudiments of 

 the scutellum and growing point, when they pass into the 

 latter, and by the time the grain is mature have formed a 

 patch of mycelium. By these means the mycelium passes 

 from one generation to another by direct infection. 



All attempts to induce the fungus to produce spores 

 have resulted in failure, and owing to the certainty of 

 securing infection in a vegetative manner the fungus is 

 apparently able to dispense with the formation of spores. 



Owing to the absence of fruit the systematic position of 

 the fungus could not be determined, but the author in- 

 clines to the view that its affinities are with the Ustila- 

 gineae or ' smuts.' 



Infected plants appear to suffer no inconvenience from 

 the presence of the fungus ; on the other hand, cultures 

 showed that infected plants were on the average more 

 vigorous, and produced a greater number of seeds than 

 uninfected plants. 



Frank, Ber. d. deutsch. Bot. Ges., 1885. 

 K 



