Geosmithia

Geosmithia
Geosmithia morbida on leaves of black walnut
Scientific classification
Kingdom:
Fungi
Division:
Ascomycota
Class:
Sordariomycetes
Order:
Hypocreales
Family:
incertae sedis
Genus:
Geosmithia

Pitt (1979)
Type species
Geosmithia lavendula
(Raper & Fennell) Pitt (1979)

Geosmithia is a genus of anamorphic fungi of uncertain familial placement in the order Hypocreales. The genus, circumscribed by Australian mycologist John Pitt in 1979,[1] is widely distributed. A 2008 estimate placed ten species in the genus,[2] but several new species have since been described. Thousand cankers disease, which affects economically important black walnut (Juglans nigra) populations in North America, is caused by Geosmithia morbida.[3]

Species in the genus are generally similar to those in Penicillium, but can be distinguished from them by forming cylindrical conidia from rough-walled phialides. Additionally, the conidia of Geosmithia do not have a green color, in contrast to the characteristic blue-grey or green-grey conidia of Penicillium. Some Geosmithia species have teleomorphic forms that are classified in the genus Talaromyces. However, Geosmithia is a polyphyletic taxon with evolutionary affinities to at least three groups of the euascomycete lineage within the Ascomycota.[4] The generic name Geosmithia honors British mycologist George Smith.[1]

  1. ^ a b Cite error: The named reference Pitt 1979 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Kirk 2008 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Derickx 2013 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Ogawa 1997 was invoked but never defined (see the help page).