364 Marshall Ward. — On a lily -disease. 
words, the germ-hyphae from the ascospores of this Peziza 
are unable to pierce the living tissues, but when they 
have been nourished in a saprophytic manner by absorbing 
food-materials derived from dead organic sources, the my- 
celium at length obtains the power of piercing the plant and 
killing it. 
De Bary gives several striking proofs of this, the simplest 
being that when the ascospores were sown on the cut surfaces 
of two carrots, one of which had been killed by boiling, the 
other still living, the germinal tubes at once entered the dead 
carrot and formed mycelia, sclerotia, etc., whereas they were 
unable to enter the living carrot at all. 
The seedlings of Petunia violacea were found to be very 
sensitive to the fungus, but if ascospores were brought into 
a drop of water with the living seedling, the germ-tubes 
failed to enter the tissues of the Petunia for days: if both 
were placed in a drop of culture-solution (instead of pure 
water), however, the germ-hyphae of the Peziza rapidly 
grew to mycelia which at once entered and destroyed the 
tissues of the Petunia-seedlings. 
Numerous other experiments led to the conclusion that 
Sclerotinia [Peziza) Sclerotiorum is a saprophytic fungus, the 
mycelium of which can become parasitic, however, if pre- 
viously invigorated by being nourished as a saprophyte. 
It is neither possible nor necessary to devote attention to 
all the interesting morphological points about this fungus, 
and the reader is referred to De Bary’s paper for many details 
passed over here. 
De Bary then goes on to show that when the mycelium has 
been nourished up to the necessary degree as a saprophyte, it 
develops the organs of attachment already referred to ; these 
organs on coming in contact with the tissues of a plant, kill 
the subjacent epidermis, etc., and, flourishing at the expense 
of the products of solution of the poisoned tissues, gather more 
strength, and send down branched hyphae in all directions. 
The action of these hyphae on the tissues is worth noticing. 
The cells in their neighbourhood are found to lose water, 
