HEART-ROT 105 
with a number of pointed sterigmata, and even in this state 
they are easily recognized. 
These conidiophores and conidia were first discovered by 
Brefeld, who sought in them support for his theory that 
basidia and basidiospores are modified conidiophores and 
conidia. He found instances in which the conidiophores 
bore three or four large conidia instead of a large number 
of smaller ones. But, even so, it is unlikely that they are 
homologous with basidia. The 
formation of basidiospores is 
generally, if not invariably, pre- 
ceded by a nuclear fusion ; but if 
these conidia are homologous with 
the conidia of types whose cytology 
has been investigated, the nuclei 
which enter them are not derived 
at all directly from a fusion nucleus. 
This distinction between conidia 
and basidiospores has been drawn 
subsequently to Brefeld’s work on 
Fomes annosus, and it is sufficient feds Fee eras: 
to justify the disfavour with which 4 conidiophore from which 
his synonym ‘ Heterobasidion an- some conidia have fallen, 
> : leaving the pointed sterig- 
nosum ’ has been received. mata; b, conidia (x 400). 
As stated above, these conidio- 
phores occur regularly in cultures, not only on bread and 
gelatine, but also on diseased wood and even on fructifi- 
cations if kept ina damp chamber. They are usually simple 
or slightly branched, but under certain circumstances, as 
when a culture is grown on bread soaked in a solution 
of dung and given plenty of room, the conidiophores may 
appear in large bundles. A single conidiophore of such 
a bundle is exactly like one of the simple conidiophores 
and has the same dimensions, but the whole bundle may be 
a quarter of an inch high. 
As these conidiophores are of such frequent occurrence in 
‘artificial cultures it is extraordinary that they should be so 
rarely met with in nature. No doubt the conditions which 
