Abstract:
Although frequently found on mounds of the grass-cutting termite genus Trinervitermes,
virtually nothing is known about the natural history of the fungal genus Podaxis (Agaricaceae)
nor why it associates with termite mounds. More than 40 species of this secotioid genus
have been described since Linnaeus characterised the first species in 1771. However,
taxonomic confusion arose when most of these species were reduced to synonymy with
Podaxis pistillaris in 1933. Although a few more species have since been described, the
vast majority of specimens worldwide are still treated as P. pistillaris. Using 45 fresh and
herbarium specimens from Southern Africa, four from North America and one each
from Ethiopia, and Kenya, we constructed the first comprehensive phylogeny of the genus.
Four of the genotyped specimens were more than 100 y old. With the exception of the type
specimen of Podaxis rugospora, all herbarium specimens were labelled as P. pistillaris or Podaxis
sp. However, our data shows that the genus contains at least five well-supported
clades with significant inter-clade differences in spore length, width and wall thickness,
and fruiting body length, supporting that clades likely represent distinct Podaxis species.
Certain clades consistently associate with termites while others appear entirely free-living.
