Echinoderma flavidoasperum Y.J. Hou & Z.W. Ge, 2020

Hou, Ya-Jun & Ge, Zai-Wei, 2020, New species of Echinoderma and Lepiota (Agaricaceae) from China, Phytotaxa 447 (4), pp. 221-236 : 223-225

Echinoderma flavidoasperum Y.J. Hou & Z.W. Ge , sp. nov. FIG. 2a–e , 3a–d

MycoBank: MB 833747

Etymology:— flavidoasperum , from the Latin flavidus = yellow, named for its similarity to E. asperum but with yellow coloration in the pileus.

Diagnosis:— Echinoderma flavidoasperum differs from E. asperum by the yellowish pileus, nearly smooth stipe discoloring light red when bruised, and broad, clavate to sphaeropedunculate cheilocystidia.

Type:— CHINA. Yunnan Province: Lijiang, Lijiang Alpine Botanical Garden, in Quercus sp. forest, elevation 2950 m, 100°11’ E, 27°0’ N, 12 August 2014, Q. Zhao 2139 (holotype HKAS 87905!)

GenBank Acc. No.:—ITS = MN810147, LSU = MN810098, tef 1-α = MN820903, rpb 2 = MN820969

Description:— Basidiomata ( FIG. 2a–e ) medium-sized. Pileus 70–90 mm, at first nearly hemispherical, then convex to plano-convex, finally expanded, surface rough, dirty white (1B1) to pale buff (1A6), dry, entirely covered with pointed or granular squamules when young; squamules stand upright with pileus growing, pointed, wart-like, pale buff (1A6), yellow (1A2), pale-ferruginous (6A2) near the center, compact, separable; context white. Lamellae free, closely crowded, white (1A1) to cream (2A2), forked. Stipe subcylindrical, 70–150 × 10–20 mm, hollow, slightly broadened towards base, upper part of the stipe (above the annulus) white (1A1), lower part creamy yellow (1A2), nearly smooth, changing light red (7A2) when bruised; context white (1A1). Annulus present, apical to subapical, ring-shaped, membranous, creamy yellow (1A2), densely covered with granular or pointed squamules, annulus and squamules easily fall off. Lacking a distinctive odor.

Lamellar trama regular. Composed of hyphae 3–10 (15) μm in diameter. Basidia ( FIG. 3b ) 13–20 × 6–8 μm, clavate, 4-spored; sterigmata 2–3 μm long; sometimes with clamps on basal septa. Basidiospores ( FIG. 3a ) [40/2/2] (6.0–)6.5–7.5(–8.5) × 2.8–3.0(–3.5) μm, Q = (1.87)1.94–2.5(2.73), Qm = 2.27 ± 0.18, subcylindrical, dextrinoid, colorless, thin-walled, smooth; apiculus small. Pleurocystidia absent. Cheilocystidia ( FIG. 3c ) 12–30 × 8–20 μm, abundant, hyaline, mostly broadly clavate to sphaeropedunculate, occasionally irregular, sometimes with basal clamp connections. Squamules ( FIG. 3d ) composed of chains of subglobose, pyriform to cylindrical enlarged cells. Terminal cells (up to 35 × 55 μm) are markedly ballooned, subspherical or ellipsoid, slightly enlarged cells at base (20–47 × 6–13 μm), basal connate hyphae subcylindrical, 4–6 μm diam., with pale yellow intracellular pigments, thin-walled. Clamp connections present in all tissues.

Habitat and Distribution:—Solitary to scattered on soil in subalpine forests dominated by Picea sp. or Quercus sp. ; basidiomata occurring in summer and autumn. Known from southwestern and northwestern China.

Additional specimen examined:— CHINA. Gansu Province: Gannan Tibetan Autonomous Prefecture, in Picea forest, elevation 2700 m, 12 August 2012, X.T. Zhu 678 (HKAS 76527!)

Comments:— Echinoderma flavidoasperum is characterized by its yellowish pileus with yellowish, yellowish-brown or pale-ferruginous pyramidal squamules, nearly smooth stipe that changes to light red when bruised, and broadly clavate to sphaeropedunculate or rarely irregular cheilocystidia. Echinoderma flavidoasperum forms a well supported clade in the phylogeny (100% BS, 1.0 PP) and is closely related to Echinoderma asperum complex. The well-known taxon E. asperum is characterized by the brown, reddish brown or dark brown sharply pointed squamules, frequently forked lamellae, stipe covered with tomentose or fibrillose veil remnants, a superior skirt-like annulus, and unpleasant smell that is similar to Lepiota cristata (Bolton) P. Kumm .. Echinoderma flavidoasperum is very similar to E. asperum and E. aff. asperum in both the basidiospore shape and the structure of the pyramidal squamules. However, E. flavidoasperum has a yellow pileus covered with darker squamules that conceal the white flesh, ring-shaped annulus, and nearly smooth stipe that change color to light red when bruised. Echinoderma hystrix differs from E. flavidoasperum by its unforked lamellae, its black eroded lamellar edges and the stipe that may exude yellowish-brown to dark-brown droplets when fresh ( Candusso & Lanzoni 1990, Shao & Xiang 1997, Kibby 2009, Clesse & Marchal, 2012). Echinoderma perplexum (Knudsen) Bon differs by its unforked or rarely forked lamellae, the stipe with cortinate annulus-zone, and basidiospores that are typically not longer than 6 or 7 μm ( Candusso & Lanzoni 1990, Kibby 2009).

Figures

FIGURE 2. Echinoderma flavidoasperum. a, b. Basidiomata of HKAS 76527. c–e. Basidiomata of HKAS 87905. Scale bars: a–e = 2 cm. Photographs by: X.T. Zhu and Q. Zhao.

FIGURE 3. Echinoderma flavidoasperum. a. Basidiospores. b. Basidia. c. Cheilocystidia. d. Squamules. Scale bars: a = 5 μm, b = 10 μm, c = 20 μm, d = 30 μm. All microscopic characters from HKAS 87905. Drawings by: Y.J. Hou.