EFB 440 - Basidiomycetes (agaricomycotina)

What is the difference between homobasidiomycetes and heterobasidiomycetes?

heterobasidiomycetes have septate basidia. homobasidiomycetes have aseptate basidia.

how are homobasidiomycetes distinguished into two groups?

based on macromorphology of the spore-bearing surface (the hymenophore). if hymenophore is exposed, it is a hymenomycete. if it is enclosed, it is a gasteromycete.

what are the characteristics of Gasteromycetes?

epigeous and hypogenous basidiocarps, no ballistospory so must rely on different spore dispersal methods (ex. animals, wind, water, weathering of basidiocarp), most are saprobes or mycorrhizal.

What is the significance of the gasteromycete pisolithus tinctorius?

ectomycorrhizal partner with Pinus, developed for use in reforestation projects, promotes growth of Pinus seedlings under unfavorable conditions, widely used in strip mine areas

puffballs and earthstars are part of this order of gasteromycetes…

lycoperdales

what does alexopoulos et al consider to be the five order of gasteromycetes?

lycoperdales, tulostomatales, sclerodermatelas, phallales, nidulariales

what are the characteristics of lycoperdales?

gleba is powdery with light-colored spores and capillitium at maturity

peridium is 2-4 layered

hymenia only observed at immature stage

symmetrical basidiospores with long sterigmata.

what are the characteristics of tulostomateles?

described as “puffballs on a stick”

early development is hypogeous (adaptative advantage in arid environments).

what are the characteristics of sclerodermatales?

earthballs

ectomycorrhizal

thick tough peridium

splits at maturity to reveal dark glebal mass

basidiospores originate in peridioles

what are the characteristics of phallales?

stinkhorns

majority are saprobes (some reportedly mycorrhizal)

young basidiocarps look like eggs usually w conspicuous rhizomorphs, egg is surrounded by 3-layered peridium

basidia with 6-8 basidiospores

gleba autodigests once exposed

spores enmeshed in foul smelling gelatinous matrix, flies disperse spores

what are the characteristics of nidulariales?

birds nest fungi and cannon ball fungus

basidiocarps at maturity are hollow

cup-like structures containing lens-shaped peridioles

spores dispersed when raindrops hit nest and eggs are expelled outward> spores then ingested by herbivores

widely distributed decomposers of cellulose

basidiocarps usually on sawdust, mulch, leaf litter, and dung.

what is the significance of the study by Hibbett et al (1997)? results?

it was the first general phylogenetic framework for homobasidiomycetes; 13 of 20 species of gilled mushrooms were found in a single lineage of ‘euagarics’ (extrapolating this, the clade is estimated to contain 87% of known gilled mushrooms), included in eugarics are non-gilled taxa (coral fungi, polypores, some gasteromycetes). the sister group of eugarics is boletales which are represented by poroid, gilled, and puffball forms. seven species of gilled mushrooms were placed outside euagarics. learned that gasteromycetes are derived from hymenomycetes and are polyphyletic.

what are the structural features associated with ballistospory?

short curved sterigmata, asymmetrical spores, buller’s drop

what are the requirements/characteristics of hymenomycetes?

evolution of exposed hymenophore, ballistospory

what structural changes occured from hymenospores to the evolution of gasteromycetes?

loss of ballistospory causing diverse spore dispersal mechanisms

how many times has the puffball form evolved?

at least three times

what are the main conclusions of habett et al?

homobasidiomycete evolution is marked by extensive convergence and parallelism (e.g. gilled mushrooms have evolved at least six times), each separate origin of enclosed hymenospore is associated with the loss of ballistospory (causally related), ballistospory has never been regained after evolutionary loss