Amylotrama leylandii

Amylotrama leylandii (G. Cunn.) Bloomfield, Davoodian, Trappe & T. Lebel, in Lebel et al., Swainsona 36: 36 (2022)

Diagnosis: Distinguished from Amylotrama banrockensis by the poorly developed, thin pileipellis, slightly smaller spores, presence of persistent basidia and conspicuous hymenial layer, and smaller isodiametric cells in the subhymenium.

Basidiomata subglobose to elongate or reniform, sometimes lobed, becoming irregular, 20–35 mm diam., 11–20 mm high; surface dry when fresh, cream to dull yellow to yellow, becoming darker upon handling, with thin, filamentous darker patches that are easily rubbed off, drying tawny-brown; basal rhizoids rare (initially concolorous, becoming dark). Hymenophore cream to dull yellow to yellow, drying yellowish to tawny brown; loculate, empty, subglobose to irregular locules, up to 1–2 mm wide, locules occasionally more compressed towards the pileipellis. Stipe absent. Columella, when present, a percurrent narrow strand < 0.5 mm wide, white. Odour mild. Taste nondescript.

Basidiospores 6.5–8.5 (–10.5) × 4.5–6.5 µm, mean=7.6×5.7 µm, Q=1.1–1.7, Q mean =1.3, statismosporic, hyaline, smooth, subglobose to slightly elongated to subovate, inamyloid, usually with conspicuous oily inclusions, moderately thick-walled. Basidia28–36×9–11.5 µm, mean=30.6×9.9 µm, abundant, persistent, forming a conspicuous hymenial layer, hyaline, sterigmata 2–4, 2.5–5 × 1–2.5 µm in size. Hymenophoral trama comprised of elongated, hyaline hyphae, 2.0–5.0 µm diam., and isodiametric subhymenial cells, the whole layer amyloid in Melzer’s reagent. Pileipellis a thin layer 15–35 µm wide, composed of a patchy layer of dark yellow, interwoven hyphae 5.5–8.5 µm diam., easily missed in sectioning. Context 730–1000 µm wide, of hyaline to yellowish, septate hyphae, 2.5–5.0 µm diam., tangled and periclinal.

Ecology and distribution: Thus far recorded as occurring solitarily or in small groups, hypogeous or emergent, in association with Eucalyptus spp. in south-eastern South Australia and southern Tasmania (collected in association with Eucalyptus obliqua at the epitype locality).

Figure 1. Phylogram from Bayesian analysis of partial TEF1-α sequences. Scale bar shows substitutions per site. Bayesian posterior probabilities (bpp) are shown at the nodes. Thickened lines indicate PP support ≥0.95. Included in the analysis but cropped from the image are sequences from four Suillus species (KU721557, KU721631, KU721709, KU721719); Suillus sinuspaulianus (KU721557) was specified as the outgroup. Xerocomoideae (node a), Boletaceae (node b), and Paxillaceae (node c, sister to Boletaceae) are indicated.