244 Transactions British Mycological Society. 
A NEW SPECIES OF 
SIGMOIDEOMYCES THAXTER. 
With Plate XII. 
By R. C. McLean. 
In November 1921 a fungus was discovered growing on the 
surface of soil in a pot in the greenhouse attached to the 
Botanical Department, at University College, Cardiff, which 
proved to be a new species of Sigmoideomyces Thaxt., a genus 
of Mucedinaceae. 
This genus has a curious history. The type species is S. dispi- 
voides Thaxt., described from Burbank, E. Tennessee; habitat 
rotten wood. A second species was found by Mrs Bayliss Elliott 
at Birmingham and described by her under the name of 
S. clathroides. The present form makes a third species. The 
genus has therefore only been seen thrice, at widely separated 
stations and on each occasion in a different specific form. 
The species under consideration was found on the soil in a 
pot in which seeds of Impatiens sultant had been sown about 
ten days previously. The soil was of the same blackish or sooty 
tinge, common in city gardens, as that on which the Birmingham 
specimens were found, giving a slightly acid reaction at about 
pH 6-0. It had not been long in the pot, but had been in use 
for potting purposes in the greenhouse for some time. The 
average temperature of the greenhouse during November is 
65°—70° F. and it is neither very light nor very well ventilated. 
As Mrs Bayliss Elliott connects the occurrence of her species 
with the presence of dead earthworms in the soil, I should say 
here that there did not appear to be any dead worms in the 
original pot of soil, though they may have disappeared by decay 
before I turned it out some time later; neither have attempts to 
recover it by enclosing samples of the soil, containing dead 
worms, in stoppered glass jars, been successful, though they 
have stood the full six months Mrs Bayliss Elliott found necessary 
for its development. This does not however disprove the inter- 
esting correlation which certainly appeared in her cultures. 
Attempts to obtain artificial cultures were unavailing, though 
several times repeated, owing to the abundance of bacteria both 
on and around the conidial fructifications. The wild growth 
disappeared after about six weeks and has not been seen since. 
The naked-eye appearance of the fungus is that of a number 
of buff-coloured, fluffy balls, about Imm. in diameter and 
2-3 mm. apart, dispersed in patches on the surface of the soil, 
the connecting, sterile mycelium being so fine as to be scarcely 
visible, These balls are the conidial fructifications, each com- 
