Hydnellum roseoviolaceum Nitare, 2021

Nitare, J., Ainsworth, A. M., Larsson, E., Parfitt, D., Suz, L. M., Svantesson, S. & Larsson, K. - H., 2021, Four new species of Hydnellum (Thelephorales, Basidiomycota) with a note on Sarcodon illudens, Fungal Systematics and Evolution 7 (1), pp. 233-254 : 248-250

Hydnellum roseoviolaceum Nitare sp.nov.

MycoBank MB837986. Figs 7A‒C , 9F .

Etymology: Epithet derived from roseo (L) = rose, referring to the rosy (rose-coloured) basidiomatal context, combined with violaceum (violet-coloured) referring to its tendency to change colour to violet-lilac.

Typus: Sweden, Härjedalen, Sveg , Fisktjärnområdet , Ytterberg , in dry, lichen-dominated, seminatural old pine heath forest on acidic sand together with Cladonia spp. , 62.072398 / 14.541843, 19 Sep. 2009, B. Petterson & S. Pratheepchuang (holotypus GB-0195936 ; isotypi O, UPS); GenBank accession: MW144374 .

Description. Basidiomata terrestrial,stipitate,fleshy and compact, simple, ofen rather small and slender. Pileus (30‒)50‒80 mm broad, convex to plano-convex, somewhat depressed in the centre, with undulating edge, ochraceous brown, tobacco/cigarbrown to reddish brown, with blackish spots in old or damaged parts. Pileus becoming more-or-less dirty black-spotted due to blackening of the hypodermis. Cuticle (pileipellis) dry, epidermis in young basidiomata forming a very thin brown tomentum, later becoming almost smooth, with no radially arranged fibrils, but with short and very small adnate hairy tufs from agglutination of tomentum hyphae (only seen under a lens),in patches sometimes cracked into small areoles. Dry specimens sometimes with small yellowish dots of excreted matter. Stipe 40‒60 × (5‒)10‒15 mm, concolourous with the pileus, tapering downwards and with a short greyish-blue rooting point. Spines strongly decurrent, but rarely reaching the middle of the stipe,up to 5 mm long,crowded, with age dark brown, but for a long time pallid at the tip. Flesh not zoned, first pinkish to rosy, becoming violaceous to lilac in about 20 s, at least in the central parts of the basidioma, more-or-less blackening when drying. No particular smell, taste mild. Chemical reaction. When adding 3 % KOH to dry specimens, both the pileipellis and flesh (trama) immediately change colour to charcoal black. Hyphal system monomitic,all hyphae simple septate,tramal hyphae in spines up to 10 µm wide. Basidia clavate, clampless, with 4 sterigmata. Basidiospores pale brownish, globose or subglobose, tuberculate, with oblique apiculus, 4.3‒5.1 × 3.2‒4.2 µm, av. = 4.7 × 3.6 µm, Q = 1.1‒1.5 (n = 2/48, measurements from the lateral side without tubercles), tubercles numerous, 0.5‒0.8 µm high, with prominent rounded apices.

Ecology and distribution: Presumably ectomycorrhizal with Pinus sylvestris . Found in old, seminatural Pinus stands (pine heaths) on dry, acidic sandy soil with Cladonia lichens. Only known from three records (two localities) in eastern central Sweden, within the middle and northern boreal vegetation zones in areas with a rather continental climate.

Additional specimens examined: Sweden, Härjedalen, Sveg, Fisktjärnområdet, Ytterberg, 29 Aug. 2008, P. Hedberg (UPS) (= first record at the type locality) ; Dalarna, Våmhus, Kumbelnäs, Bonäsheden, old pine heath on fossil eolian sand-dunes, 8 Sep. 2008, D. Broström GB-0195687 .

Notes: Among the hydnoid fungi associated with Pinus sylvestris , Hydnellum roseoviolaceum seems to be very close to, and has been mistaken for, H. fuligineoviolaceum due to its tendency to assume a lilac flesh.It differs by smaller spores,colour changes in the flesh from rose to violet (not being violet from the beginning as in H. fuligineoviolaceum ) and its mild taste (N.B. some people cannot detect the very acrid taste of H. fuligineoviolaceum ). It differs from H. glaucopus e.g. by its more intense rose-lilac flesh and by being associated with Pinus (not Picea ) on acidic, noncalcareous sites. The pictures, and partly the description, of S. fuligineoviolaceus , by Maas Geesteranus (1975a, e.g. plate 38) seem very similar to those of this new species (collections from Greece not checked) and this may be due to a misapplication of the name.

To compare the newly described species with Kalchbrenner and Fries’ original concept of Hydnum fuligineo-violaceum , the Carpathian collection from pinewoods at Olaszi (now Spišské Vlachy in Slovakia) made in Sept. 1870 and bearing Fries’ handwriting (UPS, F-173546) was studied. The collection is selected as the type by Maas Geesteranus (1975a) but he refrained from a precise designation by writing “(Holo?)Typus”. This is probably the original collection Fries refers to as v. s. (= vidi siccam; I have seen it dry) ( Fries 1874). The material consists of one small basidioma divided in three slices. The flesh is typically bluish-violet-grey (also in the spines) and the spores are 5.1‒6.2 × 3.4‒4.4 µm, av. = 5.6 × 3.7 µm (n = 32, measurements from the lateral side without tubercles), tubercles 0.6‒0.8 µm high. Kalchbrenner’s collection therefore represents, without doubt, the present concept of Hydnellum fuligineoviolaceum .

An ITS BLAST search in GenBank brings up two western North American sequences as the closest matches at 95–96 %. These sequences are both generated from ectomycorrhizal root-tips, one from a Pinus muricata stand in northern California ( Moeller et al. 2014), the other from Pseudotsuga menziesii in British Columbia ( Kranabetter et al. 2015). The sequence difference to H. roseoviolaceum consists of 15 indels and 14 gaps. We currently cannot suggest any name for this American sister taxon, if any exists. If the basidiomatal colours are like those of H. roseoviolaceum , it is likely to become misidentified as H. fuscoindicum .

Figures

Fig. 7. A–C. Hydnellum roseoviolaceum, holotype, GB-0195936, photos B. Pettersson. D. H. roseoviolaceum type locality, photo B. Pettersson. E. H. fuligineoviolaceum TU106391 (UDB011895), photo V. Liiv.F. H. fuligineoviolaceum GB-0195817.

Fig. 9. Hydnellum basidiospores. A. H. fagiscabrosum (holotype, GB-0195805). B. H. glaucopus (GB-0195722). C. H. illudens (GB-0195937). D. H. lepidum (GB-129373). E. H. nemorosum (O-F-242352). F. H. roseoviolaceum (holotype. GB-0195936).G. H. scabrosellum (holotype, GB-0195689). H. H. scabrosum (GB-0195731). Scale bar = 5 µm.