Afrocastellanoa ivoryana

Afrocastellanoa ivoryana (Castellano, Verbeken & Thoen) M.E. Smith & Orihara, in Orihara & Smith, Mycologia 109(2): 328 (2017)

Basidiomata 10–50 mm in diam, subglobose, globose, reniform to pyriform, when fresh pure white with some small areas that are gray to cream, some bluegreen stains and an undefinable pale green tinge, surface waxy, somewhat pitted in places, elsewhere smooth and somewhat powdery. In cross section the peridium appears two layered with the outer layer gray-pink and the inner pure white. Gleba solid, marbled white and red-yellow, green-yellow to pale yellow-olive, sometimes developing blue to blue-green stains when cut; locules irregularly shaped, filled. Rhizomorphs single to numerous, fine to about 1 mm wide, attached at sporocarp base, white. Columella present or absent, when present white. Taste not distinctive. Odor sweet, pleasant, slightly apple-like.

Peridium 500–1500 μm thick: Peridiopellis 30–100 μm thick, trichoderm or turf, of branched, thin-walled filamentous hyphae 2–5 μm broad, grading to inner layer context. Peridial context composed of multiple layers: Outermost layer 300–800 μm thick, of compactly interwoven or parallel, less branched, thin-walled filamentous hyphae 2–13 μm broad, partially inflated up to 35 μm in diam, the inner hyphae tend to become more frequently inflated, oleiferous hyphae present, 3–11 μm broad, partially ventricose or sinuate, strongly stained by cotton blue; middle layer present at maturity, 300–600 μm thick, of depressed remnant of non-gelatinous inflated cells forming pseudoparenchymatous tissue; innermost layer 130–200 μm thick, absent in some areas, of sparse, gelatinized, narrow, branched filamentous hyphae 1–4 μm broad. Hymenium and subhymenium absent. Basidia more or less sparsely distributed within the gleba, 14–22 × 9–13 μm, clavate to clavulate, colorless, mostly 4-spored, more rarely 2-spored. Basidiospores (9–)9.5–14.3 × (7.5–)9–12 μm (Q [length/width] = 1.04– 1.4), mean 11.8 × 9.8 μm, Qmean = 1.2 (n = 25), subglobose to broadly ellipsoid, ornamented with dense, small spines more or less angular at the base, spore walls 1.2–2 μm thick. Spiny ornamentation on spore surface up to 1.8 μm high in water, but in some cases elongated to 3.3 μm high when mounted in acidic or alkaline solutions. Clamp connections absent in all tissues.

Index Fungorum number: IF818074

Notes: Castellano et al. (2000) described the outer peridial context as composed of gelatinized hyphae 3–4 μm in diam. However, our observations of dried isotype and paratype specimens suggest that the layer is composed of non-gelatinous hyphae. Instead, we observed the innermost peridial layer consisting of gelatinous, narrow, filamentous hyphae, which was not explicitly described in Castellano et al. (2000).

Figure 1: Bayesian majority-rule consensus tree of the ITS data set of Octaviania ivoryana and allied sequences. Bayesian PP and RAxML bootstrap (BS) values (1000 replicates) are indicated above or below branches or at nodes as PP/BS. UECM = uncultured ectomycorrhizal