Pseudolepiota zangmui
Pseudolepiota zangmui Z.W. Ge, in Ge & Yang, Phytotaxa 312(2): 252 (2017)
Etymology: This new species is named in honor of the late Prof. Mu Zang, for his great contribution to the knowledge of the larger fungi of China
Basidiomata small sized. Pileus 23–45 mm broad, hemispherical to convex at first, expanding to broadly convex to applanate with age, sometimes with appendiculate margin; surface covered with furfuraceous squamules of various brown: from pale red (7A3), brown (6E4), light brown (7D4-7D5), greyish brown (7D3-7E3, 8E3), reddish grey (7B2-8B2), brownish orange (7C3-7C4), dull red (8C3), reddish brown (8E4-8E5) to dark brown (6F5-6F6); furfuraceous squamules cover nearly all pileal surface at first, and remain intact at disc with development but elsewhere diffract with expansion and receding from pileus margin, exposing the whitish pileus context beneath. Lamellae free and remote from stipe with obvious gutter, white to off white, crowded, narrow, ≤4 mm wide, with 1-3 series of lamellulae; edge entire, white, not changing color or sometimes becoming grey (24E1) on bruising, becoming grey when dried. Stipe 30–45 × 3–6 mm, subcylindric, straight or curved, white, firm throughout development; surface below the annulus covered by easily detached band-like whitish, floccose squamules with pale red (7A3) to light brown (7D4-7D5) edges; surface above the annulus glabrous, white; stipe base occasionally with rhizomorphs . Context thick in pileus, white in pileus and stipe, not discoloring when bruised, with unpleasant odor. Taste mild. Spore print white.
Basidiospores [120,6,4] (4.0)4.5–5.0(5.5) × 3–3.5 μm (mean 4.78 ± 0.32 × 3.22 ± 0.25 μm), Q = (1.29)1.43–1.67, Qav = 1.49 ± 0.1, ellipsoid, oblong in side view or in frontal view, apex rounded, smooth, hyaline to greenish white (27A2), congophilous, dextrinoid, usually with one guttule, without germ pore, slightly thick walled, becoming greyish magenta (14D4-14E4) to purplish red (14A6-14A7) in Cresyl blue. Basidia 18–22 × 5.5–6.5 µm, clavate, hyaline, four-spored. Cheilocystidia (13)18–36 × (5.0)8.0–12.5(13.0) µm, clavate, rarely broadly clavate to narrowly clavate, hyaline. Pleurocystidia not observed. Lamella trama regular to slightly interwoven, made up of subcylindrical hyaline hyphae, 7–10 μm diam. Pileal surface a subcutis layer made up of slightly interwoven cylindrical hyphae, (3)4– 6(8) µm in diam., thick walled, with brownish vacuolar pigments (occasionally interspersed with brown ones), wall brownish yellow; terminal elements mostly narrowly clavate. Stipe surface made up of regular to slightly interwoven, subcylindrical hyaline hyphae, (2.5)3.5–6(8) μm diam. Clamp connections absent.
Habitat and distribution: Saprotrophic, solitary to scattered, occasionally in clusters, terrestrial in Fagaceae forest. So far this is only known from Yunnan Province in southwestern China.
Index Fungorum number: IF820482
Figure 1. Maximum Likelihood tree inferred from the rpb2 data set. Bootstrap values >50 are indicated along nodes. The new taxa are shown in bold face.
Figure 2. Maximum Likelihood tree inferred from the ITS data set. Bootstrap values >50% are indicated along nodes. The new taxa are shown in bold face.
Figure 3. Basidiomata of Pseudolepiota zangmui (A: collection Z. W. Ge 2175; B: collection Z. W. Ge 3537).
Figure 4. Micro-morphological features of Pseudolepiota zangmui (Z. W. Ge 3537). A: Basidiospores; B: Basidia; C: Cheilocystidia; D: Pileipellis elements (squamules on pileus).
Reference:
Ge Z.W., Yang Z.L. 2017. Pseudolepiota zangmui gen. et sp. nov. (Agaricaceae, Basidiomycota), a new white-spored mushroom from China. Phytotaxa 312(2):247–255
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