Nine species of microfungi and eight basidiomycetes were assessed sing
ly and in pairwise or three-way combination for their potential capaci
ty for primary resource capture of agar media, sterile straw and steri
le roil. When single species were ranked by extension rate, results on
straw and soil agreed broadly with those from agar media, although th
e rates were much slower in straw. In pairwise and 3-way interactions
on sterile soil, colonization proceeded as predicted from the mycelial
extension rates of single species on agar, sterile soil and sterile s
traw, although extension of some species was significantly slower in c
ombination than singly. There was some agreement between the outcome o
f pairwise interactions observed on 2% malt extract agar medium and st
erile soil of four test species, and on straws in non-sterile soil of
Agrocybe gibberosa. The four species could be ranked in combative orde
r: A. gibberosa = Sphaerobolus stellatus much greater than Mucor hiema
lis and Chaetomium globosum. Cord formation by basidiomycetes was more
pronounced in soil than on agar media, and when in close proximity to
other species.