Agaricales » ‎Agaricaceae » Agaricus

Agaricus mangaoensis

Agaricus mangaoensis M.Q. He & R.L. Zhao.

Fungal Names: FN570350; Faceoffungi Number: FoF 02930

Pileus 22–30 mm in diam., convex, applanate with subumbo; margin straight, exceeding; surface dry, covered by fibrils, reddish brown, purplish brown at disc, and fading into white towards margin, appressed, turn reddish purple in wet. Context 1–2 mm thick, flesh, white. Lamellae 2–3 mm broad, free, crowded, pink or pinkish brown first, then brown in age, edge white, crenate, intercalated with lamellulae. Annulus 2–3 mm in diam., single, fragile, membranous, white, pendant, smooth on both sides. Stipe 50 × 2–3 (5–7 at base) mm, white, hollow, cylindrical, bulbous, surface above the annulus smooth, below fibrillose, white, always with rhizomorphs. Odour of almonds. Basidiome flavescent when touching, bruising and cutting. KOH reaction: positive yellow. Schäffer’s reaction: positive, reddish orange on dry specimen. Basidiospores 5.0–6.2 × 3.3–3.9 μm, [x = 5.5 ± 0.3 × 3.6 ± 0.2, Q = 1.5–1.7, Qm = 1.5 ± 0.1, n = 20], elongate, smooth, thick-walled, brown. Basidia 11–16.0 × 6.0–8 μm, clavate, hyaline, 4-spored, smooth. Cheilocystidia 15.8–43.0 × 9.6–23 μm, smooth, single, clavate, broadly clavate, hyaline or containing yellow pigments. Pleurocystidia absent. Pileipellis a cutis composed of hyphae of 3.7–15 μm in diam., smooth, cylindrical, brown, slightly constricted at septa in some cases.

Habitat: solitary on soil in forest.

Other specimens examined: Nangongshan Village, Xishangbanna, Yunnan Prov., China, 25 June 2010, collected by Zhao Rui-Lin, ZRL2010073 (HMAS275742), ZRL2010078 (HMAS275743).

Notes: This new species is represented by specimen ZRL2010056. In phylogeny, this species is sister to the unnamed specimen ZRL20151437 under the fully support of 1.0/100 PP/BS values in the clade IX (Figs 1–2). In the morphology, A. mangaoensis is easily separated from specimens ZRL20151437 because the latter has middle-sized basidiome. Some species of section Minores have tiny or small basidiome and reddish brown, purple brown caps, such as the known species A. gemloides 5, A. purpurellus 4 and A. parvibicolor 19, but their phylogenetic positions are far from A. mangaoensis, and nested in clade I and clade II respectively. In this study we introduce another new species A. minorpurpureus, which is morphologically similar to A. mangaoensis in the field. However, A. mangaoensis has elongate basidiospores and those of A. minorpurpureus are broadly ellipsoid (Q = 1.4–1.6). Based on the phylogenetic and morphological analysis, we proposed this species as new to the science. This new species is characterized by its small basidiome (less than 30 mm in diam. of pileus), reddish brown fibrils on the cap, stipe cylindrical with bulbous base and clavate cheilocystidia.

Fig. 1 Maximum Likelihood (ML) tree of Agaricus section Minores based on LSU, tef1-α, rpb2 and ITS sequences with the outgroup Agaricus campestris. The Bayesian posterior probabilities and bootstrap support values more than 0.9/50% (PP/BS) are indicated at the nodes. The branches in Bold mean the related PP > 0.95. Sequences produced from this study are in blue. “T” refers to sequences from type specimen, and “T” in red refers to the sequences from type specimen and new to science from this study.