Hydnum: A spiny genus of mushrooms

In order Cantherellales and family Hydnaceae, typified by the classical H. repandum that was first described by Linnaeus in 1753.
The genus has been collected and consumed by humans for centuries, with commons names such as “Hedgehogs”, “Sweet Tooth”, and “Wood Urchins”.
A paper in 2009 looked at ITS for the genus and found a lot more diversity than accounted for by the described species.
In 2018, this diversity was addressed using a broader study of morphology and ITS (46 sequences from 18 species and good quality sequences in UNITE and GenBank), leading to 49 species, with 22 newly described.
Traditionally three species in Europe, now four subgenera: Alba, Pallida, Hydnum, Rufescentia (in order of diversity).
The genus and lower orders generally have a worldwide or broad distribution, but species seem to be separated by continent.
Few morphological characters: Pileus and hymenium colour, central depression of pileus, basidiocarp proportions and regularity, attachment of hymenium to stipe, spore shape and size.
Distinguishing between subgenera, sections, and subsections, can require microscopy of the spores, and distinguishing between species in some groups and geographical regions requires ITS.
Both subgenera Hydnum and Rufescentia are particularly diverse and have species that overlap in morphology.
H. reginae was recently described from the UK, and analysis of ITS and LSU suggests this is the European H. cf. albidum, and H. albidum s.s. is an American species.
H. reginae is placed in subgenus Alba and seems to be more closely related to the species around H. cremeoalbum.
This analysis of ITS and LSU for subgenera Alba, Pallida, and Hyndum provides further support, although support for Alba is still relatively weak.

UK situation, records checked in GBIF (some could be missing):

H. repandum (Subgenus Hydnum: Section Hydnum): ~2,000 records.
H. rufescens (Subgenus Rufescentia: Section Rufescentia: Subsection Rufescentia): ~700 records.
H. ellipsosporum (Subgenus Rufescentia: Section Rufescentia: Subsection Tenuiformia): One record from Wales, but CBIB considers the species widespread and suggests that it has been mistaken for H. rufescens.
H. c.f umbilicatum (Subgenus Rufescentia: Section Rufescentia: Subsection Tenuiformia): Apparently records elsewhere, European concept.
H. reginae (Subgenus Alba): No records but described from the UK, considered rare in the UK as noticeably different to other species present.

I wonder if the novelty of the species and difficulty of separation could mean that more European species are present. I guess sequencing the ITS from more UK collections would help.

Literature:

Grebenc, T., Martín, M. P., & Kraigher, H. (2009). Ribosomal ITS diversity among the European species of the genus Hydnum (Hydnaceae). Anales Del Jardín Botánico De Madrid, 66(S1), 121–132. https://rjb.revistas.csic.es/index.php/rjb/article/view/333/327

Niskanen T, Liimatainen K, Nuytinck J, Kirk P, Ibarguren IO, Garibay-Orijel R, Norvell L, Huhtinen S, Kytövuori I, Ruotsalainen J, Niemelä T, Ammirati JF, Tedersoo L. (2018). Identifying and naming the currently known diversity of the genus Hydnum, with an emphasis on European and North American taxa. Mycologia, 110(5), 890-918. http://www.nlmushrooms.ca/science/2018%20Identifying%20and%20naming%20the%20currently%20known.pdf

Kibby, G., and Liimatainen, K. (2022). Hydnum reginae newly described from Britain. Field Mycology, 23(3), 77-80. https://www.britmycolsoc.org.uk/application/files/9916/5937/2438/Field_Mycology_Vol_233_August_2022.pdf

Posted on November 4, 2023 06:52 PM by