Russula ferruginea subsp. panamensis Corrales & Manz 2022, subsp. nov.
Creators: name: Buyck, Bart
name: Eyssartier, Guillaume
name: Armada, François
name: Corrales, Adriana
name: Hembrom, Manoj Emanuel
name: Rossi, Walter
name: Bellanger, Jean-Michel
name: Das, Kanad
name: Dima, Bálint
name: Ghosh, Aniket
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Russulales
Russulaceae
Russula
Russula ferruginea
Russula ferruginea subsp. panamensis corrales &amp; manz

description: 119. Russula ferruginea subsp. panamensis Corrales & Manz, subsp. nov.
(Figs 16 B-D; 19-22)
DIAGNOSIS. — Russula ferruginea subsp. panamensis Corrales & Manz, subsp. nov. differs from Colombian subsp. ferruginea Corrales & Vera, subsp. nov. by terminal cells of hyphae in the pileipellis that are not occasionally to frequently inflated close to their bases, they are shorter on average and slightly narrower. These differences are most evident near the centre of the pileus, where average values of Colombian terminal cells are 18.5-32 × 4.1-4.6 µm and of Panamanian ones 13.5-15.5 × 3.4-3.5 µm.
HOLOTYPE. — Panama. Chiriquí province, Quebrada Honda watershed, Fortuna forest reserve, 80°45’09.4”N, 82°14’23.6”W, 1191 m asl., associated with Oreomunnea mexicana, Quercus sp., 19.XII.2012, Anna Giessel & Meike Piepenbring A 28 (UCH, PMA).
MYCOBANK. — MB841771.
GENBANK. — MZ604292 (holotype).
ETYMOLOGY. — Referring to the distribution area of the subspecies, which is so far only known from Panama.
ADDITIONAL MATERIAL STUDIED. — Panama. Chiriqui province, Zarciadero site near Bocas del Toro Road, Fortuna Forest Reserve, 8°45’24”N, 82°16’47”W, alt. 1000 m, in forest dominated by Oreomunnea mexicana, terrestrial, 19.IV.2012, A. Corrales 099 (ARIZ).
DESCRIPTION
Pileus
Small to medium sized, 45-46 mm in diam., when mature plane with depressed centre; margin strongly tuberculate-striate to c. half of the radius; cuticle near centre shiny when wet, rugulose, near margin radially cracking, color near margin light brown turning to light yellowish brown or beige, near the center dark grey-brown, deep blackish brown to almost black.
Lamellae
Moderately distant, up to 4 mm broad, pale cream-white, lamellulae and furcations occasional, edge even and concolorous.
Stipe
35 × 7 mm, cylindrical, longitudinally striate, near lamellae greyish white, towards base light brown, with darker reddishbrown spots at the base, interior hollow.
Context
2 mm thick at the middle of the pileus radius, fragile, greyish brown, flesh turning reddish brown when cut and getting more red spots at the base when bruised, taste and odour not observed.
Spore print
White.
Spores
(6.8-)7.1-7.4-7.7(-8.2) × (5.3-)5.6-6-6.4(-6.8) µm, mainly broadly ellipsoid, Q = (1.09-)1.18-1.24-1.29(-1.4); ornamentation of moderately large, dense [(4-) 6-8 in a 3 µm diam. circle] amyloid, low, obtuse warts, (0.3-)0.5-0.8(-0.9) µm high, fused in pairs or short chains [(0-)1-4 fusions in the circle], connected by occasional to frequent line connections [(0-) 1-3 in the circle], isolated warts absent; suprahilar spot not amyloid, smooth, relatively large.
Basidia
(29-)32-35.4-39(-45) × (5.5-)7.5-8.9-10(-11) µm, fusiform or clavate, 4-spored; basidiola first cylindrical or ellipsoid, then clavate, c. 5-9 µm wide.
Hymenial cystidia
Numerous, c. 1800-2400/mm2, (37-)54-63.7-74(-90) × (5.5-)6.5-7.7-9(-11) µm, mainly fusiform or lanceolate, pedunculate, apically acute, with 1-6µm long appendage, thin-walled, often originating deeply in the subhymenium; contents almost homogenous, yellowish, with few faint dispersed granulations, turning dark brown in sulfovanillin; near the edges of lamellae smaller, (30-)32.5-40.3-48(-64) × 5-6.4-7(-8.5) µm, clavate, rarely lanceolate or fusiform, acute, occasionally also apically obtuse, apically with small, 1-3 µm long appendage.
Marginal cells
(7-)10-13.1-16(-19) × 4-5.9-7(-8.5) µm, similar to basidiola but shorter, occasionally mixed with some basidia.
Pileipellis
Orthochromatic in Cresyl Blue, sharply delimited from the underlying context, 70-130 µm deep; suprapellis very thin, up to 30µm deep, near margin disrupted and absent on some parts, composed of more or less horizontally oriented or repent and sometimes clustered hyphae; vaguely delimited from the thick, gelatinized subpellis formed by loose, irregularly oriented, 2-4 µm wide hyphae, that are denser and horizontally oriented near the trama.
Acid-resistant incrustations
Absent.
Hyphal terminations
Near the pileus margin loose or in dispersed clusters, composed of one or two cells, thin walled; terminal cells (8-)10-15.8-21(- 31) × 2.5-3.4-4(-5)µm, mainly cylindrical, occasionally clavate, apically obtuse; subterminal cells branched or not, of constant width and usually as long as wide. Hyphal terminations near the pileus centre similar,terminal cells (6-)10-14.6-19(-28) ×(2-)2.5- 3.4-4(-5) µm, frequently distinctly flexuous-nodulose.
Pileocystidia
Near the pileus margin dispersed, always 1-celled, mainly subulate, occasionally fusiform or lanceolate, thin-walled, (21-)32-60.9-89(-165) × (3-)3.5-4.6-5.5(-6) µm, apically acute-pointed, mostly with a 1-2µm long, pearl-like appendage; contents slightly yellowish with indistinct granulations, hardly reacting in sulfovanillin. Pileocystidia near the pileus centre relatively frequent, (20-)23-30.7-40(-65.5) × (3-)3.5- 4.5-5.5(-7) µm, usually subulate or lageniform, otherwise similar to those near the margin of the pileus.
Cystidioid hyphae
Dispersed in subpellis but more frequent near the context, sometimes similar to cystidia but longer, contents often more conspicuous, oleipherous and turning dark brown in sulfovanillin and red after carbolfuchsin treatment.
Clamp connections
Absent from all tissues.
NOTES
The Colombian collections described here as R. ferruginea sp. nov. are very similar to the Panamanian collections ARIZ (Corrales 99) and UCH (A28). We were unable to find any differences in the field, but this might be caused by the lack of details in field descriptions of the Panamanian samples. Under the microscope, Colombian collections have terminal cells of hyphae in the pileipellis occasionally to frequently inflated near bases that are on average longer and also slightly wider than terminal cells in the pileipellis of Panamanian collections. These differences are especially apparent near the pileus centre, where average values of Colombian terminal cells are 18.5-32 × 4.1-4.6 µm and of Panamanian ones are 13.5-15.5 × 3.4-3.5 µm. Our multi-loci analysis shows support to distinguish the Panamanian samples as different taxa from the Colombian samples but this was not supported by the individual gene analysis of LSU or rpb2. The fixed nucleotide differences between them are three in ITS, five in coding parts of tef1 α and three in rpb2 region. Because of few morphological differences and very close phylogenetic proximity, we decided to follow the criteria used byVera et al. (2021) and assign the rank of subspecies to populations of R. ferruginea sp. nov. separated by the disjunction at the Isthmus of Panama. The clade of R. ferruginea subsp. panamensis subsp. nov. based on sequences of the ITS region (Fig. 6) also includes the sequence KM594970, that was obtained from an ectomycorrhizal root tip of Oreomunnea mexicana from Panama (Corrales et al. 2016).
description: Published as part of Buyck, Bart, Eyssartier, Guillaume, Armada, François, Corrales, Adriana, Hembrom, Manoj Emanuel, Rossi, Walter, Bellanger, Jean-Michel, Das, Kanad, Dima, Bálint & Ghosh, Aniket, 2022, Fungal biodiversity profiles 111 - 120, pp. 23-61 in Cryptogamie, Mycologie 20 (2) on pages 51-54, DOI: 10.5252/cryptogamie-mycologie2022v43a2, http://zenodo.org/record/7828891