Isozyme analysis possesses predictive value and may reveal aspects of
the natural history of a species that are not otherwise obvious. Worki
ng on this premise, isozyme analysis was performed on Lycoperdon pyrif
orme to shed light on the attributes of this species that most likely
influence the distribution of genetic diversity observed among seven c
ollection sites within the study region (i.e., central Arkansas, north
eastern Kansas and northwestern Missouri). Forty-nine unique multilocu
s isozyme phenotypes were identified from cultures isolated from immat
ure glebal tissue of 310 basidiocarps collected from the surface of de
caying logs (similar to one isozyme phenotype per log). Numerical and
cluster analyses to determine similarity of phenotypes indicated that
these group out randomly and not according to collection site. Further
analyses of isozyme data were performed, grouping phenotypes together
into populations according to collection site. Isozyme bands were par
titioned by locus based on the assumption that these represent alleles
and interpreted on the assumption that the dikaryotic mycelia of this
puffball species are physiologically diploid. Nine of the eleven puta
tive loci examined were polymorphic, with a mean of 3.6 alleles/polymo
rphic locus. Mean heterozygosity for populations varied from 0.200 to
0.345, suggesting the possibility that outcrossing occurs in this spec
ies. Unweighted pair group method cluster analysis displayed marginal
grouping of populations based on geographic proximity. Genetic diversi
ty statistics indicate that genetic differentiation among; populations
is low (G(ST) = 0.122). Patterns of variation observed in this specie
s suggest that gene flow has acted as a homogenizing force in this spe
cies within the region sampled.