Pleurotus in New Zealand

There are relatively few species of Pleurotus in New Zealand, although the genus is superficially similar to Hohenbuehelia, Scytinotis, Crepidotus and Conchomyces. The genus Pleurotus was last revised in New Zealand by Segedin (1995). However there are a number of issues with that revision which undermine the reliability.

P. purpureo-olivaceous has a dark brown polished caps, a rubbery texture and pale greyish gills. It can be mistaken for Hohenbuehelia species in the petalodes group and so the gills should always be checked, with a hand-lens and preferably microscope, for the absence of the large metuloid cystidia characteristic of Hohenbuehelia. Some darker forms of P. australis can look similar but are not rubbery and the gills are not grey. Phylogenetically P. purpureo-olivaceous is distinct from all other species of Pleurotus (unsurprisingly). The remaining NZ species are rather similar, with cap colours variable from cream to brown (but not dark brown and polished), and a stipe varying from absent to lateral and fruitbodies occurring singly to clustered on wood. They can only reliably be distinguished by micro-characters.

P. djamor is the name given to a cluster of phylogenetically related but distinct entities. Some of the cultivated shop versions in this group are yellow or pink. The indigenous version has caps that are brownish. The complex is represented in New Zealand by P. parsonsiae, and that name should be used in preference to P. djamor. Examination the type of P. parsonsiae held at Kew, confirms it sits with the P. djamor complex and should be recognised as an independent species. There is some doubt that Segedin in her 1995 re-description examined the correct specimen as her description differs considerably from the recent re-examination, which demonstrates the presence of skeletal hyphae. Members of the group always have some skeletal hyphae in the stipe and are consequently rather tough. By skeletal I mean hyphae with refractive thickened walls (and with or without clamps). Sometimes the term dimitic is used but perhaps not appropriately. The sequence data tell us that P. parsonsiae is identical to some collections from Kenya, whilst the Cook Islands have their own version of 'P. djamor'. The name P. opuntiae has been used incorrectly in NZ for P. parsonsiae. It should be noted that P. parsonsiae, P. australis and P. pulmonarius are all confirmed as occurring on Cabbage Tree (as well as other trees).

A recent paper (Zervakis et al, 2019) discussing the P. djamor complex is in error regarding comments on P. parsonisae. The type collection was not studied by the authors and they accepted erroneous subsequent re-descriptions by Segedin et al 1995.

Sequences of verified collections of P. australis from New Zealand are phylogenetically intermixed with collections from Australia and represent the same species in both countries. The cap can become quite dark brown and shiny but the fruitbody is not rubbery and gills not greyish like P. purpureoolivaceous. Some species of Pleurotus produce 'coremia' - a black slimy exudate on the growing caps which consists of asexual spores (conidia). This asexual stage has been referred to the genus Antromycopsis. Pleurotus australis is one of these species and is therefore placed in the subgenus Coremiapleurotus along with P. cystidiatus and P. fuscosquamulosus. In Segedin's 1985 paper the species is assigned to subgenus Pleurotus without coremia and that is clearly incorrect. In addition she places Pleurotus purpureo-olivaceus in subgenus Coremiapleurotus. On phylogenetic grounds that seems doubtful and I have not observed coremia in that species. In my opinion some collections of P. australis and P. purpureo-olivaceous were confused by Segedin, but unfortunately a number of collections mentioned in the paper seem to have been misplaced and cannot be re-examined. In fact it is possible that Stevenson's type collection of P. purpureo-olivaceus is in fact P. australis, which would make the name a later synonym of P. australis, and a new name would be needed for our large purplish species on beech. P. rattenburyi is almost certainly a synonym of P. australis and not P. purpureo-olivaceus. To resolve this confusion the type collections of all the relevent species housed at Kew require re-examination (for P. purpureo-olivaceous, P. rattenburyi and P. crawfordiae).

P. pulmonarius is yet another species complex with our version clustered with material from Asia. P. pulmonarius forms a distinct clade with P. ostreatus & P. eryngii.

P. velatus was described from New Zealand by Segedin et al as a species possessing a veil. However re-examination of the type indicates no visible veilar remnants. The cap is sparsely velutinate in younger frbs but not as a consequence of veilar remnants. The type is the only collection and more collections showing the purported characters are required to validate its recognition. It may just represent a form of P. pulmonarius or P. djamor.Such variants are known elsewhere.

The true Oyster MushroomP. ostreatus is not present in natural environments in New Zealand. It is present as an introduction in cultivation. An old collection from a supermarket was found to be this species, although without information on the original source. P. ostreatus was listed as an Unwanted Organism but that status has recently changed and the species can now be imported and grown.

 

1

Frb rubbery in texture. Cap dark brown to purplish brown, polished. Gills pale grey. Spores < 9 um long.

P. purpureoolivaceous

1’

Frb not rubbery in texture. Cap usually paler. Gills cream to yellow. Spores > 9um long.

2

2

Skeletal hyphae absent in all tissue Cap grey to brown (sometimes dark). Spores 11 x 4, Q=2.8 (often longer)

P. australis

2’

Cap paler – cream to tan/fawn. Spores 10um or smaller, Q < 2.7

3

3

Cap grey to tan/fawn. Always some skeletal hyphae in the stipe. Spores 10 x 4um, Q=2.5

P. parsonsiae (P. djamor NZ)

3’

Cap cream to tan/fawn. Skeletal hyphae absent or restricted to lamellae trama. Spores 10 x 4um, Q=2.5

P. pulmonarius

References:

Segedin, B.P.; Buchanan, P.K.; Wilkie, J.P. 1995: Studies in the Agaricales of New Zealand: new species, new records and renamed species of Pleurotus (Pleurotaceae). Australian Systematic Botany 8: 453-482

Zervakis G.I., Venturella G., Fryssouli V., Inglese P., Polemis E., Gargano M.L., 2019. Pleurotus opuntiae revisited – An insight to the phylogeny of dimitic Pleurotus species with emphasis on the P. djamor complex. Fungal Biology, 123(3): 188-199

Posted by cooperj cooperj, August 03, 2016 23:24

Comments

Thumb

Really! From all those names in NZFungi there are only four species. Also interesting that Greta Stevenson's Pleurotus parsonsiae is a version of Pleurotus djamor. All of a sudden the genus Pleurotus just got easy. Thanks for these posts which really help to clarify what is here in our forests.

Posted by codfish almost 5 years ago (Flag)
Thumb

We do have and undescribed Sarcomyxa in NZ.
There are sequences, but unfortunately no photos or descriptions to go with them.
Were the spores amyloid?

Posted by cooperj over 2 years ago (Flag)

Add a Comment

Sign In or Sign Up to add comments