36 Transactions British Mycological Society. 
septate filaments. Meanwhile lateral branches arise and anasto- 
moses take place between the hyphae. Later, balls of hyphae 
appear here and there in the culture and on the sides of the 
tube or flask containing them, usually some distance from the 
ends of the hyphae. These balls are very similar to those which 
appear in the cells of the root, being formed by the rolling up 
of the ends of young growing filaments, and often becoming 
very compact. When seen in the host cells this method of growth 
suggests adaptation to the needs of the special environment, and 
its presence in cultures might lead to the supposition that the 
character is so impressed upon the fungus that it also shows it 
when living free. The character is, however, not rare in the 
group in which we must classify this fungus. 
As the mycelium becomes older shorter filaments arise with 
very short and swollen segments, which are apparently rich in 
food reserve. (It was this appearance that caused Bernard to 
place the fungus in the genus Oospora when he first studied it.) 
These filaments ramify abundantly and in certain forms anasto- 
mose amongst themselves and give rise to yellow or brown 
sclerotia* (Figs. 4 and 5), small spherical bodies formed of inter- 
twined and massed hyphae. These structures are capable of 
withstanding drought and other inclement conditions and are 
remarkably tenacious of life. Bernard has pointed out that these 
swollen filaments are very like those which occur in Rhizoctonia 
violacea Tul.t which is common on potatoes, lucerne and other 
crops, where it forms small, blackish, irregular sclerotia, and he 
considers that the orchid fungi fall into the same genus. He 
classed the fungi obtained from about twenty orchids as three 
species, Rhizoctonia repens, R. mucoroides and R. lanuginosa. 
The first, which was by far the most commonly isolated (Laelia, 
Laelio-Cattleya, Spiranthes, Paphiopedilum, Cymbidium, Aerides, 
Bletilla, Coelogyne), does not form sclerotia. R. mucoroides was 
found in Phalaenopsis and Vanda, and R. lanuginosa in Odonto- 
glossum (Figs. 4 and 5). Burgeff, unaware of Bernard’s latest 
results, proposed a new genus Orcheomyces for the reception of 
the orchid fungi. He fully describes fifteen species, naming 
them after the orchid from which he obtained them andmentions 
another fourteen by name: he divides them into five main 
groups. 
A discussion of the different systematic interpretations given 
by Bernard and Burgeff would be out of place here and for 
convenience the more generally adopted name Rhizoctonia will 
* Sclerotia are known in all groups of fungi, often reaching considerable 
dimensions, e.g. the size of a man’s head in Polyporus Mylittae (the “ black 
fellows’ bread”’ of Australia). 
t+ Corticium vagum B. and Br. var. Solani Burt. 
