TRANSACTIONS OF SECTION K. 923 
5, Bulgaria polymorpha (Wettstein) as a Wood-destroying Fungus. 
By R. H. Birren, Cambridge. 
Bulgaria polymorpha (Wettstein), B. inquinans (Fr.), is stated by Ludwig to 
be parasitic on oak, The author has examined its anatomy, and studied it in pure 
cultures on wood and in food-material. The white early growth soon becomes 
bright orange; small rounded elevations are afterwards formed, which are incipient 
reproductive bodies. 
The action on wood is examined in some detail. The fungus grows better on 
oak than on pine. The lignified wood-elements are de-lignified. Details as to 
the reactions in various stages of its destructive action are dealt with in the paper. 
The author does not regard this fungus as of great importance as a wood-destroy- 
ing fungus in this country. 
6. On a Disease of Tradescantia fluminensis and T. sebrina. 
By Ausrrt Howarp, B.A., Scholar of St. John’s College, Cambridge. 
During the summer it was found that two species of Tradescantia, viz. T. flu- 
minensis and T. sebrina, growing in greenhouses, were being attacked by a fungus. 
Diseased leaves and stems were in many cases found to be covered with long white 
conidiophores. Pure cultures were made of this form, and the complete develop- 
ment was followed out by the hanging-drop method. The fungus proved to be a 
species of Botryosporium. Some difficulty was experienced in obtaining this form 
free from another fungus, a species of Cladosporium. Infection experiments, made 
with the spores and mycelium of the Botryosporiwm under the most diverse con- 
ditions, failed, nor would the mycelium infect the healthy leaves if previously 
invigorated by cultivation. 
It was found in the case of the naturally growing host plants that infection 
started either on the upper side of the leaf as a small semitransparent dot, or from 
the margin. Tangential sections of the upper epidermis of the leaf containing one 
of these transparent areas, and also portions of the infected margin, when grown 
in hanging drops, showed in all cases hyphz on the epidermis, which gave rise to 
the same species of Cladosporium as that mentioned above, occurring as a weed in 
the Botryosporium cultures. The development of this Cladosporium was then 
followed out from a single spore by the hanging-drop method, and infection 
experiments were made which proved successfnl. 
7. Demonstration of Vermiform Nuclei in the Fertilised Embryo-Sac of 
Lilium Martagon. Sy Miss Etnen SarGant. 
8. On the Sexuality of the Fungi. By Harotp WAGER. 
SATURDAY, SEPTEMBER 16. 
Joint Discussion with Section B on Symbiosis.—See p. 692. 
