Chlorophyllum globosum (Mossebo) Vellinga

Ge, Zai-Wei, Jacobs, Adriaana, Vellinga, Else C., Sysouphanthong, Phongeun, Walt, Retha van der, Lavorato, Carmine, An, Yi-Feng & Yang, Zhu L., 2018, A multi-gene phylogeny of Chlorophyllum (Agaricaceae, Basidiomycota): new species, new combination and infrageneric classification, MycoKeys 32, pp. 65-90 : 75-76

Chlorophyllum globosum (Mossebo) Vellinga

Type.

CAMEROON. Yaoundé, alt. 780 m, growing on humus in shade under tree, 1 November, 1996, D. C. Mossebo, D. C. Mossebo 98-1 kept in the Herbarium of University of Yaoundé I (non vide).

Description.

Basidiocarps medium to large-sized (Figure 3C). Pileus 5.0-20.0 cm broad, ovoid to subglobose when young, expanding to parabolic, convex to broadly convex with age; margin inflexed, with short, fine striations; surface covered with yellowish-white (3A2) to yellowish-grey (4A2), greyish-yellow (4B3-4B4), brownish-orange (6C6) to greyish-brown (5D3) squamules. The squamules remain intact at disc, but elsewhere diffract with expansion and recede from pileus margin, displaying the white to yellowish-white (2A2, 3A2, 4A2) felted or fibrillose background which turned pastel red to red (9A4-6) when touched. Lamellae free and remote from stipe with obvious gutter, white to orange-white (5A1-2) when young, turning pastel red to red (9A4-6) when touched, pastel green to greyish-green (29A4, 29B4) when fully mature, crowded, ventricose and narrow near pileal margin, crowded, up to 8 mm wide, with 1-2 series of lamellulae; edge finely fimbriate, white to yellowish-grey (4A2). Stipe 8.5-28.0 × 1.0-3.1 cm, subcylindric, tapering to apex, with bulb-like, 3.0-3.4 cm wide; glabrous, white to brownish-orange (6C3-6), hollow, nearly stuffed, with an annulus about 1/3 away from the stipe apex (Figure 3C); sometimes with distant white fibrillose at apex zone, turning pastel red to red (9A4-6) when touched, with white rhizomorph connected to substrate. Context thick, white in pileus and stipe, brownish-orange (6C3-6) at apex zone, paler to middle zone and white downward base, discolouring pastel red to red (9A4-6) in both pileus and stipe context when bruised, with mushroom odour. Taste mild. Spore print yellowish-white (2A2) to pale yellow (2A3) to greyish-green (29D3-5, 29D5-6).

Basidiospores [40,2,2] (10.5)11.5-12.0 (12.5) × (8.0) 8.5-9.0 μm (mean 11.8 ± 0.4 × 8.7 ± 0.3 μm), Q = 1.3-1.4 (1.5), Qav = 1.4 ± 0.05, broadly amygdaliform in side view, ovoid in frontal view, with truncate apex, smooth, greenish-white (28A2), congophilous, dextrinoid, thick-walled (Figure 6A), becoming purplish-red (14A6-14A7) in cresyl blue. Basidia 29-38 × 12.0-14.0 µm, clavate, hyaline, 4-spored, sometimes 2-spored, rarely 1-spored. Cheilocystidia 42-65 × (15.0)18.0-29.0 µm, clavate occasionally with slightly long stalk, hyaline, sometimes with greyish-yellow vacuolar pigments. Pleurocystidia absent. Pileipellis a hymenidermal layer made up of subcylindrical hyphae (5.0-11.0 µm in diam.), slightly thick walled, with dull yellow (3B3) vacuolar pigments; terminal elements with rounded or attenuate apex, mostly narrowly clavate. Clamp connections not observed.

Distribution.

Known from Cameroon, Nigeria and South Africa in Africa and from China, India and Thailand in Asia.

Ecology.

Saprotrophic, solitary to scattered, terrestrial.

Specimens examined.

CHINA. Yunnan Province: between Yuanmou and Yongren, 28 June 2006, Z.W. Ge 2006-1 (HKAS 52741). SOUTH AFRICA. 2229 BD Kamkusi, Farm Ludwigslust 163 MS, − 22°16.27'S, 29°49.02'E, alt. ca. 580 m, 12 March 2014, Van Der Walt, R 957 (PREM 62147), growing in sandy soil under Sickle bush ( Dichrostachys cinerea ) and Umbrella thorn trees ( Vachellia tortilis , formerly Acacia tortilis ); 2229 BD Kamkusi, Farm Ludwigslust 163 MS, alt. 584m, growing in sandy soil under Sickle bush and Umbrella thorn trees, 7 February 2014, Van Der Walt, R 869 (PREM 62148); same locality, 9 March 2014, Van Der Walt, R 936 (PREM 62149); 2229 BB Beit Bridge, Farm Matolege 133 MS, alt. ca. 580m, shady area under blue thorn ( Senegalia erubescens , formerly Acacia erubescens ), compost-rich, adjacent to lawn in hunting camp, 12 February 2014, Van Der Walt, R 892 (PREM 62150); 2229 BB Beit Bridge, Farm Wimpsh 139 MS, alt. ca. 604 m, loam soil, amongst grass - adjacent to seasonally waterlogged pan, 12 January 2014, Van Der Walt, R 821 (PREM 62151); same locality, 14 February 2014, Van Der Walt, R 900 (PREM 62152). THAILAND. Chiang Mai Province: Mae Taeng District, Pongduad Village, 16°06'N, 99°43'E, 780-810 m, 16 June 2010, P. Sysouphanthong, P37 (MFLU100555); Chiang Rai Province: Muang District, Ratjabhat University campus, 30 August 2012, P. Sysouphanthong, 2012-21 (MFLU121815).

Discussion.

Chlorophyllum globosum was originally described from Cameroon in the genus Macrolepiota . It was said to differ from Macrolepiota odorata "by the globose pileus and the ochraceous spore print" ( Mossebo et al. 2000). In fact, the pileus does not stay globose during maturation but becomes broadly convex (Figure 3C). Based on the morphological characters such as the truncate basidiospores and its phylogenetic position, Vellinga (2002) transferred it to Chlorophyllum . The authors’ molecular phylogeny confirms that C. globosum nests in Chlorophyllum close to C. molybdites , but it differs from the latter in having a pale yellow spore print and clavate cheilocystidia. This species was first described from Africa, but its presence in several Asian countries is confirmed.