1899] THE CEREAL RUST PROBLEM 341 
Fusarium lycopersici, Sace., the fungus causing the tomato disease. 
This discovery was announced in a footnote to Collenette’s paper 
quoted above. During further experiments with seed from diseased 
tomatoes sent by Collenette, I was able to corroborate the presence of 
slender hyphae in the testa of the seed, and furthermore obtained both 
the Diplocladiwm and Fusarium stages of the fungus by placing sections 
of the diseased seeds in a culture medium. 
The above experiment leaves no doubt as to the fact of seed pro- 
duced by a diseased tomato fruit being able to perpetuate the disease, 
due to the presence of latent mycelium—not mycoplasma—in the 
testa of the seed. 
Experiments with Hollyhock seeds gave similar results. When 
the carpels are attacked by the Hollyhock rust—Puccinia malvacearum, 
Mont.—the testa of the seeds frequently contain mycelium, and such 
seed when sown, if it germinates at all, gives origin to a large per- 
centage of diseased seedlings, the teleutospores of the fungus appear- 
ing on the hypocotyl and on the cotyledons in abundance. This 
experiment is of considerable importance, as the fungus belongs to the 
same genus as those producing rust on cereals. 
Ustilago vaillantii, Tul., a fungus infesting the anthers, and some- 
times also the ovary, of Scilla bifolza, and other allied plants, has been 
under constant observation for the past six years with the object of 
ascertaining its complete life-history, which is intended for publication 
in detail in the near future. The leading points in its history bearing 
on the question at issue are as follows:—Quite young seedlings may 
be infected by spores present in the soil. A perennial mycelium is 
formed in the short stem at the base of the bulb; from this hyber- 
nating mycelium hyphae pass into the flower-stalk each season ; this 
mycelium finally reaches the anthers and the ovary. The mycelium 
is only present in the tissues at any given time for a length of about 
2 mm.—in other words, as the mycelium creeps up the tissues of the 
flower-stalk it deliquesces and disappears behind, the growing tips of 
the mycelial strands only being at any one time evident, and when it 
has passed into the anthers there is not a vestige of mycelium to be 
found in the filaments of the anthers. All this takes place while the 
flower is in the bud condition, and the whole inflorescence is yet 
underground. When the fruit is attacked all the seeds are often 
completely destroyed, their position being occupied by a powdery black 
mass of fungus spores. In other instances only some of the seeds are 
destroyed, others present in the same fruit remaining apparently 
healthy; but on microscopic examination of such seeds slender 
mycelium can often be detected in the testa. Apparently healthy 
seeds obtained from a fruit having some of its seeds destroyed by the 
fungus, when sown in sterilised soil, and freed from adhering fungus 
spores by proper methods, always yield a large percentage of diseased 
seedlings, the mycelium soon being quite conspicuous in the delicate 
23—NAT. SC.—VOL. XV. NO. 93. 
