Entoloma-bloxamii-sensu-lato-in-Britain

Naming UK collections of Big Blue Pinkgill (Entoloma bloxamii sensu lato), and distribution mapping of the segregate taxa.
 

Brian Douglas and Martyn Ainsworth, 15 Jan 2017.

Information derived from, and expanding upon, Ainsworth et al. (2018) Big Blue Pinkgills formerly known as Entoloma bloxamii in Britain: E. bloxamii s. str., E. madidum, E. ochreoprunuloides forma hyacinthinum and E. atromadidum sp. nov. Field Mycology 19(1), 5-15.


Entoloma bloxamii (Big Blue Pinkgill) is a robust blue to greyish blue to brown mushroom with white-to-pink gills that typically occurs in grassland habitats. For many years E. bloxamii has been considered a species of conservation concern in the UK, originally due to low numbers of fruit-body records and habitat loss. Initially and provisionally red list assessed as Endangered in Great Britain (Ing 1992), as records increased it become apparent that E. bloxamii was more widespread than originally thought, resulting in a provisional Red List assessment of Least Concern in Great Britain and the Isle of Man (Evans et al. 2006). Despite this increase in the known UK population, E. bloxamii was considered rather rare in its European context, being threatened in over 50% of countries in which it has been red-listed (Dahlberg & Croneborg, 2003). This justified its inclusion as a UK Biodiversity Action Plan species (prior to devolution), and its current status as a priority species for the purposes of the conservation of biodiversity in England, Wales, Scotland and Northern Ireland (see current list of species with conservation designations at http://jncc.defra.gov.uk/page-3408, accessed 10/01/2018).

Recent investigations into the taxonomy of Entoloma species have revealed previously unexpected species diversity in this group (Morgado et al. 2013), and E. bloxamii-like species are no exception. Prior to Morgado et al. (2013) only E. bloxamii and E. madidum had been considered as potential Big Blue Pinkgills in GB&I, although taxonomic opinion as to whether these species should be synonyms, and which name should be preferred, has changed back and forth over time. Morgado et al. (2013) stabilised the names and concepts of E. bloxamii and E. madidum by designating well-characterised epitype and neotype specimens to represent these taxa, and provided a reference DNA-based phylogeny against which new specimens could be compared. Morgado et al. (2013) also raised E. prunuloides var. obscurum (previously considered a variety of the common E. prunuloides (Mealy Pinkgill) to species level as E. ochreoprunuloides, and described a blue-tinged form of this new species as E. ocreoprunuloides f. hyacinthinum. The new blue-tinged form was discovered and described from Pembroke by David Harries of the Pembrokeshire Fungus Recording Network, and thus constituted a third Big Blue Pinkgill for Britain.

DNA sequencing of E. bloxamii voucher specimens at Kew prior to Morgado et al. (2013), undertaken as part of the Natural England Species Recovery Project (SRP), had already indicated that the Big Blue Pinkgills in Britain comprised more than just two species. However, it was impossible to give names to these taxa in the absence of fixed species concepts, reference DNA barcodes, or photographs of living specimens. The publication of Morgado et al. (2013) allowed comparison of the Kew sequences with their dataset, confirming that E. bloxamii, E. madidum, and E. ochreoprunuloides f. hyacinthinum are British; and identifying which species occur where, albeit for a limited number of samples. Examination of the Morgado et al. (2013) and Kew SRP datasets also suggested that there seemed to be a fourth species occurring at several sites in Britain. Unfortunately, the number of DNA sequenced specimens at the time was quite small, and many collections lacked photographs of fresh fruit bodies which might help morphologically differentiate these species.

To increase the sample size of new collections, and to make sure these were accompanied by photographs of fruit bodies when fresh, E. bloxamii s.l. (sensu lato, or in the broad sense) was included as one of 100 Target Species for the Lost and Found Fungi project. So far, the efforts of contributors and volunteers have resulted in over 34 new records of E. bloxamii s.l., most accompanied by voucher specimens and photographs of fresh fruit bodies. DNA sequencing of some of these specimens provided enough data to allow the description of a fourth Big Blue Pinkgill – the dark blue E. atromadidum. This species appears distinct from the much lighter E. madidum, the browner (with violet tinges) E. ochreoprunuloides var. hyacinthinum, and the more lilac and larger spored E. bloxamii s.str. (sensu stricto, or in the narrow sense).

Our understanding of the true distribution of these four species (and any other as-yet-unnamed Big Blue Pinkgills) is still at an early stage. Revising the GB&I distribution map of E. bloxamii s.l. into its segregate taxa will take many more new records, photographs, voucher specimens, and DNA sequencing of representative collections. Due to the large number of sites and records it may only be possible to resolve a fraction of these occurrences in the short term, especially considering that multiple Big Blue Pinkgills can co-occur at some sites. While this process is happening (and at least until the end of the Lost and Found Fungi project in 2019), this webpage aims to provide up-to-date record and distribution data for what we know of Big Blue Pinkgills in GB&I.


Distribution mapping of the Entoloma bloxamii s.l. complex in GB&I


Big Blue Pinkgill voucher specimens held in the RBG Kew Fungarium



Identification guide:

Cap and stipe very dark navy blue to dark blue-grey or blue-black, not fading, often with a fibrillose (fibrous), radially grooved or rivulose (marked with irregular grooves) texture, especially towards the margin.

Maximum spore size <8.5 µm, spore size range 6.2–8.3 x 6.4–8.0 µm, average 8.2 × 8.3 μm (Ainsworth et al. 2018)

Entoloma atromadidum.

Images © M.W. Storey.

Map

Cap and stipe very bright neon-blue to sky-blue, fading to light grey; or slightly darker blue but not quite approaching navy or black-blue tints, lacking significant brown colouration.

Maximum spores size <8.5 µm, spore size range 5.9–7.6 × 5.8–7.5 μm, average 6.8 × 6.7 μm (Morgado et al. 2013).

Entoloma madidum s.str. (matching the neotype concept).

Images first right © C. Kelly, second right © M. Richards.

Map

Cap and stipe brownish with blue or violet-blue tinges.

Maximum spore size <8.5 µm, spore size range 5.9–7.1 × 5.7–7.2 μm, average 6.6 × 6.4 μm ((Morgado et al. 2013).

Entoloma ochreoprunuloides var. hyacinthinum.

Images first right and second right © D.J. Harries.

Map

Lighter violet blue to light-to-mid grey to brown colouration and chunky appearance.

Maximum spore size >8.5 µm, spore size range 7.4–9.4(−10.8) × 6.7–9.7 μm, average 8.2 × 8.3 μm (Morgado et al. 2013)

Entoloma bloxamii (matching the epitype concept).

Image first right © A.M. Ainsworth, second right © J. Doe.

Map
Colouration not clearly as above, or material in poor condition, with maximum spore sizes >8.5 µm, most spores >7.5 µm

Probably Entoloma bloxamii s.str., although a futher undescribed species (Entoloma sp. aff. bloxamii "Eaves Wood") is grey brown with similar sized spores.

Image first right E. bloxamii s. str. © J. Doe, second right Entoloma sp. aff. bloxamii "Eaves Wood" © J. Weir.

 

Colouration not clearly as above, or material in poor condition, with maximum spore size <8 µm, spores typically ≤7 µm

 Probably E. madidum or E. ochreoprunuloides f. hyacinthinum.      

Notes:

  • Morphological characters differentiating these taxa are currently are limited to the distinctive colours shown by many of the DNA-sequenced collections, combined with spore sizes.
  • Very fresh material may be required to reliably identify the small-spored species based on colour, especially when distinguishing darker forms of E. madidum which may approach the lighter shades of E. atromadidum under certain light conditions.
  • Colour variations for E. ochreoprunuloides include light brown, blue-tinged and pink fruit bodies.
  • E. bloxamii can be most reliably identified morphologically by maximum spore size approaching 9-10 microns, although very brown-grey collections warrant DNA-sequencing due to the presence of a putative undescribed species with similar spore sizes (Entoloma sp. aff. bloxamii “Eaves Wood”).

Further collections, with good quality photographs of multiple fruit bodies in different stages of development, would be greatly appreciated for DNA-sequencing, further distribution mapping, and inclusion in the British National Collection of fungi at Kew. Please contact Brian Douglas at b.douglas@kew.org if you have any such material to contribute to the Lost and Found Fungi project.


References:

Ainsworth et al. (2018). Big Blue Pinkgills formerly known as Entoloma bloxamii in Britain: E. bloxamii s. str., E. madidum, E. ochreoprunuloides forma hyacinthinum and E. atromadidum sp. nov. Field Mycology 19(1), 5-15.

Dahlberg, A. & Croneborg, H. (2003). 33 threatened fungi in Europe. Complementary and revised information on candidates for listing in Appendix I of the Bern Convention. Document T-PVS (2001) 34 rev. 2. Swedish Environmental Protection Agency and the European Council for the Conservation of Fungi, Uppsala. https://rm.coe.int/168074686e, accessed 11/01/2018.

Evans, S.E., Henrici, A. & Ing, B. (2006). Preliminary Assessment: The red data list of threatened British fungi. http://www.fieldmycology.net/Download/RDL_of_Threatened_British_Fungi.pdf

Ing, B. (1992). A provisional Red Data list of British fungi. The Mycologist 6(3): 124–128.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith