Amanita pseudovalens var. tartessiana R. Arraiano-Castilho, A. C. Silva, C. Vila-Vicosa, M. R. Castro, L. Morgado & P. Oliveira 2022, var. nov.

Amanita pseudovalens var. tartessiana R.Arraiano-Castilho, A.C.Silva, C.Vila-Viçosa, M.R.Castro, L.Morgado & P.Oliveira, var. nov.

HOLOTYPE. — Portugal. Alentejo, Beja district, Odemira, Luzianes A, 12.IV.2015, A. C. Silva, Ode12 (holo-, PO [PO-F2143]).

ISOTYPE. — Portugal. Alentejo, Beja district, Odemira, Luzianes A, 21. III.2015, A. C. Silva, Ode02 (iso-, PO [PO-F2133]).

ADDITIONAL SPECIMENS EXAMINED. — Portugal. Alentejo, Beja district, Odemira, Luzianes A, 21.III.2015, A. C. Silva, Ode01; Ode03; 28.III.2015, A. C. Silva, Ode04; 04.IV.2015, A. C. Silva, Ode08; Luzianes B, 04.IV.2015, A. C. Silva, Ode05; Ode06; Ode07; 12.IV.2015, A. C. Silva, Ode10; Ode11; Portalegre district, Portalegre, 27.IV.2015, N. Alegria, Ode16; Évora district, Portel, 07.IV.2010, R. Arraiano-Castilho, P01 (for basidiospores only).

ETYMOLOGY. — The epithet refers to the ancient Tartessian civilization (ТαΡΤησσός) located in the south-west of the Iberian Peninsula (Celestino Pérez & López-Ruiz 2016).

PHENOLOGY. — Late winter and spring.

HABITAT. — Mediterranean, in association with Cistus spp., typically on compact, acidic and eroded soils, corresponding to regressive shrubland stages of evergreen oak forests (Fig. 5).

DISTRIBUTION. — Portugal. Reported from the NUTS III regions of Alentejo Litoral, Baixo Alentejo, Alentejo Central and Alto Alentejo.

MYCOBANK. — MB 845582.

INDEX FUNGORUM. — IF 559871.

NOTES

This taxon corresponds to the Portuguese specimens described in this study. It differs from the autonym by its habitat (on acidic schist soils, with Cistus spp.), the ellipsoid to oblong, infrequently subcylindric basidiospores, and longer basidia (Table 6). Such differences are not considered to be at the rank of form. A species rank is currently not supported, due to the lack of genetic resolution of the nrDNA sequences.

Both taxa share, aside from the characters in common with other species of series Amidella, the vernal fruiting season, the medium to small size, and the indistinct odour (Table 6), and can be confirmed with the Aps diagnostic PCR primers described in Table 2.

DESCRIPTION

To describe the new species, we used fresh materials obtained from sites A and B near Luzianes in spring 2015 (Ode01- 12 except Ode09) and the basidiospores from a collection in the Portel county (P01, near Monte Novo, spring 2010) and another from São Mamede Park near Monte Carvalho, Portalegre county (Ode16, spring 2015). All specimens used in this description were deposited in the PO herbarium (see Material and Methods).

Pileus

Flat to slightly depressed, convex at the margin, expanding to a diameter of 7.5 cm. Most collections whitish in situ, turning rose/ochre with either aging, handling, or scratching. A pale grey plaque from the universal veil is frequently present. Some collections present brownish scales close to the margin (Fig. 3B, C). Margin thinly appendiculate.

Hymenophore

Adnexed ascending, white, turning rose/ochre with either aging, bruising or scratching, with lamellulae.

Stipe

Almost cylindrical,slightly tapering toward the apex,non-bulbous, base obconical. Concolorous with the pileus, with a very fugacious annulus (Fig. 3H). A scale covering can be seen below the annulus region (Fig. 3A; C; E; F). Height not longer than the diameter of the expanded pileus, thickness 2.2 cm at the most.

Veil

Universal veil leaving a sac-like thick volva with a lobed margin, pale grey, with an internal ridge raised in contact with the stipe (Fig. 3H); often it remains also as a single pale grey plaque on the pileus.

Partial veil leaving a fugacious non-membranous annulus at roughly two-thirds of the stipe height, and narrow remnants on the pileus margin.

Context

Concolorous with the surface, homogeneous, relatively compact, non-putrescent. Odour indistinct. Reaction with 10% FeSO 4 on rehydrated samples from the stipe develops an immediate change to greenish grey that lasts a few minutes.

Basidiospores

White, amyloid, ellipsoid to oblong, average length 11.78 µm, average width 6.97 µm, average length/width ratio (Q) 1.696 (Table 5), overlapping the A. ponderosa sporograph but not the one for A. curtipes f. pseudovalens (Fig. 4). Due to the lack of spore print, collections Ode01 and Ode16 were not included in the summary calculations. Statistical testing rejected the hypothesis of homogeneity among the collections included in the summary statistics, for all three variables (Appendices 4; 5). Indeed, the heterogeneity among collections was the rule (Table 5; Appendix 8): Ode10 had longer spores and higher Q, bordering on standard A. pseudovalens comb. nov., stat. nov. limits; Ode08 had wider spores and lower Q, even more than A. ponderosa, while Ode11 had spores of average Q values but small size. Nested ANOVA (within and between sites) also suggested heterogeneity within sites for the three variables, but only for length and width between sites.Site A collections have on average significantly higher values (Appendix 6).

Basidia

Clavate, with 4 sterigmata, base unclamped, average length 56.9 µm (equal to the median), range 41.0-73.4 µm, n = 123. The measurements were obtained from collections Ode02b, Ode05, Ode06a, Ode07, Ode08, Ode10, Ode11 and Ode12, revealing a normal distribution of the global data (Shapiro-Wilk’s W = 0.990, P = 0.555). On average, similar basidia sizes were observed across all collections, although Ode11 had a higher average length of 63.9 ± 5.0 µm (Appendix 7).

Universal veil

Sagital sections (Ode02, Ode07, Ode11, Ode12) revealed a thin outer layer, 80-100 µm deep, composed of slightly interwoven, longitudinally oriented hyphae, very compact and 10 µm wide (as measured in transversal sections), from which thinner hyphae, very loose, projected outwards (not found in Ode11). Many of the latter hyphae had a slightly widened, bulbous termination. No clamp connections were observed. The remainder of the structure was composed of more loosely packed longitudinal, slightly wavy hyphae, with very conspicuous lacunae interpreted as remnants of larger inflated, ellipsoid to oblong, hyphal elements. Measurement of these lacunae in Congo Red SDS stained sections (Ode02, Ode07, n = 41), under low magnification, gave an estimate of 40-71 µm length (average 54 µm, C. V. 17%) by 20-46 µm width (average 33 µm, C. V. 16%).