Conocybe cylindrospora T. Bau & J. Liu, 2018

Liu, Jing & Bau, Tolgor, 2018, New species and new records in the genus Conocybe (Bolbitaceae) from China, Phytotaxa 357 (4), pp. 261-274 : 265

Conocybe cylindrospora T. Bau & J. Liu sp. nov. Fig. 3 , 7A

MycoBank MB 823260

Etymology: referring cylindrical to ellipsoid-oblong shape of basidiospores.

Diagnosis:— Conocybe cylindrospora is characterized by light orange, ochre-brown to reddish brown pileus, cylindrical to ellipsoid-oblong basidiospores, and lecythiform with a 2-4 μm long neck and small captivate head cheilocystidia, and presence of caulocystidia similar to cheilocystidia.

Type:— CHINA. Jilin Province: Changchun city, Jilin Agricultural University (43° 48′ 248″ N, 125° 24′ 28″ E), September 5 th 2016, Tolgor Bau & Jing Liu, HMJAU42440 (Holotype!) ; same location, September 8 th 2016, Jing Liu HMJAU42441 (Isotype) .

Description:—Pileus 0.5–2 cm broad, obtusely conical to conical at first, then expending to broadly campanulate, occasionally conico-convex, light orange when young, later turns into brownish orange to ochre brown or reddish brown (6A4, A5, 6C8, 7D7–D8, 8D8) with darker center (7C6–C 7, 8E7, 8E 8), hygrophanous, becoming salmon to light orange (6A4, A5) on drying, translucent surface smooth, not or faintly pubescent, shiny when moist. Context thin, concolorous with surface. Odour and taste not distinctive. Lamellae 0.5–2 mm broad, adnexed, crowded with three series of lamellulae, ochraceous at first, later turning into orange-brown to rusty brown with whitish edge. Stipe 5–7.5 × 0.1–0.15 cm, cylindrical with subbulbous to bulbous base, surface covered with whitish pubescent–striate, orange brown at first, then pale brownish orange, occasionally in older basidiocarps pale brown, on drying pale ochre, context solid to hollow.

Basidiospores (12.0–)12.2–14.7(–14.9) × (5.1–)5.4–7.1(–7.3) μm, Q=(1.72)1.96–2.17(2.27), Q m =2.03(±0.08), cylindrical to ellipsoid-oblong, with monoguttulate to multiguttulate oil droplets, pale orange-brown to orange-brown in ammonia (5C8, 6C8, 7C8), thick walled, apical germ pore present. Basidia 17–24 × 12–15 μm, clavate, hyaline to lightly yellowish, clamp-collection present at the base of basidia, 4-spored. Cheilocystidia 15–26 × 7–10 μm, lecythiform with short neck and small captivate head, hyaline. Pleurocystidia absent. Lamellae trama is parallel, consisting of cylindrical to inflatened hyphae 4–40 μm broad, hyaline to ochraceous. Stipe cuticle a thin cutis made up by cylindrical hyphae 2–8 μm broad, with hyaline to pale orange yellow, thin-walled. Caulocystidia predominantly lecythiform with short neck and captivate small head, rarely subglobose. Clamp-connection present. Pileipellis 22–39 × 15–29 μm, an epithelioid hymeniderm, consisted by clavate and spheropedunculate elements, with hyaline thin wall. Pileocystidia absent. Clamp-connection present.

Habit and habitat:—Saprotrophic, solitary, or in groups, on soil in grass or edge of forest rich in nutrient.

Distribution:— China.

Note:— Conocybe cylindrospora belongs to the sect. Conocybe due to presene of lecythiform cheilocystidia with a 2–4μm long neck and small captivate head, and caulocystidia similar to cheilocystidia ( Hausknecht & Krisai-Greilhuber 2006). Within sect. Conocybe , the present species is easily distinguished by its pileus with orange hue and cylindrical to ellipsoid-oblong basidiospores.

With regard to the colouration of pileus, C. cylindrospora is similar to C. ambigua Watling and C. pubescens (Gillet) Kühner as well as C. watlingi Hauskn. However , Conocybe ambigua is characterized by 2-spored basidia and lecythiform with 1.4–2.8 × 1.4–2.8 μm neck and small global head, mixed with clavate element and lageniform with very long cylindrical neck caulocystidia. Conocybe pudescens is easily distinguished by its ellipsoid-oblong to subamygdaliform spores, and caulocystidia similar to that of C. ambigua . Conocybe watlingi is easily separated by rooting stipe ( Hausknecht 2005, Arnolds 2005).

Based on the molecular phylogenetic analysis, Conocybe cylindrospora cluster with C. merdaria (clade A) and C. macrospora with significant support value, while the presence of distinctly 2-spored basidia easily differentiate C. merdaria and C. macrospora from that of the newly described species (Arnolds 2005). Conocybe merdaria is characterized by ellipsoid-oblong to ovoid-oblong (Q=1.5–2.0, Q m =1.6–1.85) basidiospores, and Conocybe macrospora is limited by ovate-elliptic in (Q=1.6–1.9, Q m =1.78±0.08) basidiospores ( Arnolds 2003, Prydiuk 2007), while C. cylindrospora is distinguished by cylindrical to ellipsoid-oblong. Except Conocybe cylindrospora , both Conocybe merdaria and Conocybe macrospora have pileocystidia ( Arnolds 2003, Malysheva 2011). The significant support in the Bayes tree should be limited by the numbers of species in that clade, if more species are added to the dataset, support value would be lower.

Figures

FIGURE 3. Conocybe cylindrospora HMJAU42440 A) Basidiomata B) Basidiospores C) Basidia D)Cheilocystidia E)Caulocystidia F) Pileipellis Bars:A=1cm; B–F=10μm.Illustration by Jing Liu.

FIGURE 7. A) Conoybe cylindrospora (HMJAU42440) B) Conocybe serrata (HMJAU42442). C) Conocybe fuscimarginata (HMJAU42438) D)Pholiotina vexans (HMJAU42439) Bars: a and d=10 mm. photo a–b by Yu-peng Ge; photo c and d by Tolgor Bau.