28 
HOLTE HMANN : FUNGUS CULTURES 
and Caryota urens, are particularly remarkable. A reddish 
brown gelatinous mass of varying size is, as a rule, to be 
seen on wounded stems. This is the sweet sap, which 
often flows in great quantity, especially from the cut ends 
of young inflorescences. In it I always found the spores of 
fungi, in one case of no fewer than twenty-six species, and 
all were more or less germinated, some even with a large 
mycelium. The species found were Basidiomycetes, 
Mucorineæ, üstilagineæ, and others. My first attempts to 
use this exudation for fungus cultures were without success, 
and need not be described here. 
The sap of Arenga saccharifera and Caryota urens is dried 
by the natives and brought to market, without further 
purification, as palm sugar, consisting of sugar, vegetable 
acids, and salts. It was a dilute solution of this in water 
which proved so excellent a medium for the cultivation of 
different genera of fungi. Palm sugar is everywhere 
common and cheap in Java and Ceylon, and is not difficult 
to obtain in Europe. The various genera of fungi require 
different degrees of concentration of the medium. Some 
fungi germinate easily in a 25 per cent, solution, others 
only in one of 5-6 per cent. Definite rules can hardly be 
laid down. I have been in the habit, when the spores will 
not germinate in a 10-11 per cent, solution, of trying a 
weaker one. 
The sap, being an excretion product of the plant, naturally 
contains salts and other chemical combinations besides 
sugar, and it is to this that its great advantages as a nutritive 
medium are to be attributed — sugar alone would not be so 
suitable. Only in rare cases must anything be added to it 
to ensure germination.^' 
On account of the impurity of the Java and Ceylon sugar, 
the watery solution must be filtered before use, and various 
measures must be taken to free it from the numerous 
E.g., see my ‘‘ Mycologische üntersuchungen,’' p. 20. 
