Russula galbana T. Lebel
Cap: hemispherical; 15 – 25 mm diameter; glabrous, slightly viscid when wet; cream to pale brown (5A2, 5B3), with an olivaceous tinge (4B3), margin incurved and remaining so (secotoid).
Stipe: cylindrical; 10 – 20 × 5 – 11 mm; glabrous; white; almost half length inserted into cap.
Gills: adnexed; white becoming cream; visible as gills at base but almost loculate next to cap flesh.
Flesh: white, firm, unchanging on exposure to air.
Chemical reactions: FeSO4 on stipe: salmon; Guaiac on stipe base: nil.
Spore print: cream.
Spores: globose; 8 – 10 × 8 – 10 µm, average 9.2 ± 0.7 × 9 ± 0.7, Q = 1 – 1.06, average Q = 1.03 ± 0.015; amyloid ridges form a partial reticulum.
Basidia: clavate; 30 – 35 × 10 – 15 µm; four spored.
Cheilocystidia: numerous, fusoid, some mucronate; 45 – 75 × 8 – 20 µm; extend beyond basidia.
Pleurocystidia: as cheilocystidia.
Pileipellis: an ixocutis
Habitat: in wet sclerophyll forest with Eucalyptus tereticornis and Eucalyptus grandis.
Notes: only known from two sites in Queensland and seemingly rare. The small secotoid fruit bodies with a pale yellow brown or pale olivaceous cap and a firm white stem should be recognisable in the field.
Collections examined: PL310315, Willets Road, Bellthorpe, Bob Philpot, 29 Mar 2015.
Sequestrate fungi are an important part of the funga of Australia and are present in several mycorrhizal genera in the Agaricomycetes. There are a number of sequestrate species in the Russulaceae of Australia and Russula galbana appears to be the least known. It was described from Queensland and best meets the IUCN criteria.
Russula galbana is an ectomycorrhizal fungus growing in Eucalyptus dominated forests in Australia. It is only known from two collections in North Queensland made 20 years ago and one recent collection in the Sunshine Coast hinterland. The species is possibly naturally rare, but it may also possibly just be overlooked because it is found beneath Eucalypt leaf and bark litter in relatively undisturbed forests. The twenty year gap between the first two sightings and the recent collection and the fact that only one of the locations is in a protected area, underline the need for an assessment.
Australia. There are only two sub-populations, one in North Queensland on the Atherton Tablelands and the other at Bellthorpe in the Blackall Ranges of the Sunshine Coast hinterland. These two areas are over 1500 kms apart. Some of the intervening area along the Great Dividing Range might have suitable habitat for this fungus, but for the present it must be assumed that we have two subpopulations that do not exchange genetic material.
Only three sites are known and there is only a single record in the last 20 years. This is not an easy fungus to find, occurring in Eucalyptus dominated forests where there is often deep litter from stripped bark on the ground so we may anticipate that there may be a number of undiscovered sites for this species. But to balance that, the northern sites are in areas that have been relatively well surveyed by mycologists including the Mycoblitz survey in North Queensland and truffle searches in both localities. Taking these factors in to account we think it reasonable to assume that there are likely to be at least five times as many sites yet to be discovered.
The ecosystem in which this species is found is relatively intact in the northern locality with 90% of its pre settlement extent still present, although the quality of the habitat has undoubtedly declined due to logging, grazing and fire. The southern locality has experienced a greater loss of habitat and less than 50% of the pre-settlement level survives.
Population Trend: Uncertain
This species of Russula has only ever been found in wet sclerophyll forests where it is likely to be mycorrhizal with Eucalyptus and/or possibly with Allocasuarina species. In its southern locality it occurs in tall Eucalyptus forest (12.12.15a) dominated by mature E. grandis. The northern sites are in drier forest (9.5.9a) with Corymbia clarksoniana.
The habitat in which this species is located is only partially protected for the site in the Dinden Forest Reserve. The other two sites are not formally protected. Grazing by both feral and introduced farm animals occurs at all the sites. Fire is used as a management tool for the northern forests and its effect on these mycorrhizal fungi is not well understood. The two known localities in north Queensland are both surrounded by plantation forestry and grazing lands and are subject to a regular burning regime at 2 – 15 year intervals. The locality in the Sunshine coast hinterland is on privately owned land where the current owner favours conservation.
Both subpopulations face risks from possibly inappropriate fire regimes. The northern sites are periodically burnt and this is known to reduce the presence of mycorrhizal fungi. Robinson (2007) shows a twelve fold reduction of Russulales in burnt areas when compared to un-burnt sites.
There is also some grazing pressure from exotic species. Cattle grazing has been allowed at both the northern localities in the past, wild pigs are also present. Deer and wild pigs are present in the southern locality. Whilst the precise effects that these activities have on the fungal component of the ecosystem is unknown, circumstantial evidence suggest that forests grazed by exotic animal species have a lower fungal diversity than natural forests in Australia.
Not protected, and no management plan. This fungus is listed as ‘Least Concern’ by the Queensland Government although they have not carried out any formal assessment.
There are no specific recommendations available for this species. Research on the biology of this species and mycorrhizal fungi in general is needed to formulate effective management plans.
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Dahlberg A. & Mueller G.M. (2011) Applying IUCN red-listing criteria for assessing and reporting on the conservation status of fungal species. Fungal Ecology 4: 147-162.
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Robinson R.M. and Tunsell V.L. (2007) A list of macrofungi recorded in burnt and unburntEucalyptus diversicolorregrowth forest in the southwest of Western Australia: 1998 – 2002. Conservation Science W. Aust. 6 (1) 75 – 96.
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