An Addition to the Cryptogamic Flora of the 
Royal Botanic Garden. 
BY 
MALCOLM WILSON, D.Sc., and H. F. TAGG, F.L.S. 
Physarum gyrosum, Kost. 
Specimens of this organism, which belongs to the Mycetozoa, 
were found in a greenhouse in the Royal Botanic Garden in May 
1g19. The sporangia were discovered by Mr. Laurence Stewart 
amongst moss, on the surface of the soil in a pot in which seeds 
from India had been planted, and it is probable that the species 
was introduced with the seed. 
The sporangia are clustered, and give rise to net-like plasmo- 
diocarps several millimetres in diameter, which are seated on a 
dull red hypothallus ; the sporangium wall is grey, with clustered 
deposits of white lime-granules. The capillitium forms a scanty 
network of hyaline threads with large lime knots; the spores 
are pale brownish-violet, spinulose, and 7—10 wu in diameter. 
This species has not been previously definitely recorded in 
Britain. Berkeley probably found it in a cucumber frame in 
Northamptonshire, naming it Didymium daedalium, Berk. et Br., 
but the type specimen has not been preserved. The form 
described by Massee from a palm-house at Kew, and named 
Physarum cerebrinum, was also probably the same species. 
Physarum gyrosum has been tecorded from the Botanic 
Gardens at Berlin, from Ceylon, Japan, and from North and 
South America. 
We desire to record our thanks to Miss G. Lister, to whom we 
are indebted for confirming the naming of Physarum gyrosum 
and for information concerning this species. 
Printed under the sepage of His Majesty’s < Office 
& Co., Ltp., Edinbur; 
{Notes, R.B.G., Edin., No. e pu t921.] 
