Pulveroboletus africanus De Kesel & Raspe

Badou, Sylvestre A., esel, Andre De, Raspe, Olivier, Ryberg, Martin K., Atsu K. Guelly, & Yorou, Nourou S., 2018, Two new African siblings of Pulveroboletusravenelii (Boletaceae), MycoKeys 43, pp. 115-130 : 115

Pulveroboletus africanus De Kesel & Raspe sp. nov. Fig. 2 a–f

Illustr.

Sharp (2011, page 41, ut Pulveroboletus aff. ravenelii ).

Holotype.

Togo, Central Province, Fazao National Park, 08°44'31.9"N, 0°48'17.4"E, 6 June 2008, elev. 500 m, on the ground in a gallery forest with Berlinia grandiflora (Vahl) Hutch. & Dalziel, Uapaca guineensis Müll.-Arg. and Pandanus sp., leg. A. De Kesel, De Kesel 4650 (BR!, BR 5020165390056, duplicate in TOGO).

Etymology.

Epithet refers to its very wide distribution throughout tropical Africa.

Description.

Basidiomata medium-sized, covered by a general veil when young. Pileus 60-70 mm diam., at first broadly convex then pulvinate to plano-convex, upper layer dark brown (6E6-6F6), dry, mat, tomentose to felty, very soon cracking, becoming tomentose-scaly, bright yellow (2A4-5) in the deeper layers, predominantly yellow with age; scales appressed, slightly fibrillose, leather brown to greyish-brown (6E4-5), thicker and darker in the centre, thinner, paler and more diffused towards the margin; margin at first incurved, appendiculate with age, vivid yellow, beset with sulphur-yellow pulverulent material. Hymenophore tubulate, separable, straight to slightly sinuate, almost free around the stipe or depressed and then only slightly decurrent with a tooth; tubes up to 10 mm long, yellow to greyish-yellow (1B3), cyanescent when cut; pores regular, mostly round or slightly angular, slightly elongated around the stipe, small (14-16/mm), yellow (1A2-2A2), with age greyish-brown (5E4-6), cyanescent. Stipe cylindrical, 60-80 × 8-12 mm, central, solid, uppermost part vivid yellow (2A4-5), often with some reddish fibrils and smooth, lower part sheathed from the base up with a mat, dry, fibrillose-cottony, greyish to brownish-grey (5 –6EF3– 4) layer, the latter cracking transversally, forming brownish-grey to olive brown patches (4DE4-6), first exposing a greyish-white layer, then the bright yellow deeper layers; ring at first prominent, loose membranous-cottony, vivid yellow (2AB3-5), covering the pores, later tearing, leaving fibrillose to membranous material on both pileus margin and upper third of the stipe, pulverulent, becoming greenish from spores.

Context yellowish-white in the pileus, marmorated yellow (1-2A2) - yellowish-white in the stipe, yellow towards the base of the stipe, cyanescent in all parts. Basal mycelium and rhizomorphs relatively thick, yellowish-white (2A2) to yellow. Odour strong fungoid. Taste not recorded. Spore print greenish-olive (fresh 3D4 in Rammeloo 5720).

Macrochemical reactions: tubes brown to reddish-brown with KOH and NH4OH (in collections Rammeloo 5922 and De Kesel 2163).

Spores (8.4)8.6 –9.5–10.3(– 10.6) × (4.5)4.5 –4.9– 5.3(5.4) µm, Q = (1.77)1.79 –1.93– 2.07(2.09), broadly ellipsoid, smooth, pale yellowish-brown in 5% KOH and Melzer’s reagent, thin-walled, inamyloid. Basidia 4-spored, 22-35 × 8-12 µm, clavate, hyaline, sterigmata up to 3-4 µm long, without clamp connection. Cheilocystidia abundant, cylindrical to narrowly fusiform, (31.9 –)32.1–42.6–53(– 48.8) × (6.1 –)5.6–7.2–8.7(– 8.6) µm, thin-walled, hyaline. Pleurocystidia similar to cheilocystidia, not abundant. Hymenophoral trama subregular, with poorly defined mediostratum. Pileipellis a tomentum composed of irregularly arranged hyphae, the latter cylindrical, of similar shape, 3.8-5.1(6.5) µm wide, slightly thick-walled (0.5 µm), with brownish intracellular pigment (persistent in 5% KOH), smooth, with pulverulence in places. Stipitipellis a tomentocutis composed of elements similar to the pileipellis. Partial veil composed of cylindrical hyphae, 3-6 µm wide, thin-walled and smooth. Clamp connections present in pileipellis tissue, small, frequent.

Additional collections.

BENIN, Atacora Province, Kota, 10°12.680'N, 1°26.723'E, 30 Aug. 1997, 490 m a.s.l., gallery forest with Berlinia grandiflora and Uapaca guineensis , De Kesel 2023 (BR 5020074869827); ibidem, 10°12.699'N, 1°26.786'E, 17 Jun. 2000, 490 m a.s.l., De Kesel 2824 (BR 5020126377836); ibidem, 10°12.665'N, 1°26.750'E, 30 Jun. 2002, 510 m a.s.l., De Kesel 3500 (BR 5020152209163); Borgou Province, Wari Maro, 9°09.884'N, 2°09.595'E, 20 Jun. 1998, 300 m a.s.l., savannah woodland with Isoberlinia doka Craib & Stapf and Uapaca togoensis Pax, De Kesel 2163 (BR 5020112674574); BURUNDI, Bururi Province, Mugara, 04°02'S, 29°31'E, 16 Nov. 1978, 1050 m a.s.l., Brachystegia woodland, Rammeloo 5720 (BR 5020019368651);); ibid., 18 Nov. 1978, Rammeloo 5788 (BR 5020019374713); ibid., 20 Nov. 1978, Rammeloo 5811 (BR 5020032463654); ibid., 29 Nov. 1978, 950-1050 m a.s.l., Brachystegia woodland, Rammeloo 5922 (BR 5020019378759); ibid., Rumonge-Mutambara, 4°0.756'S, 29°29.599'E, 11 Jan. 2011, 950 m a.s.l., miombo woodland with Brachystegia utilis Burtt Davy & Hutch. and B. bussei Harms, Degreef 673 (BR); GUINEA, Labé Prefecture, Fouta Djalon, N of Tountourou, 13 Jul. 1988, 1000 m a.s.l., mountain woodland with Uapaca chevalieri Beille, Thoen 7977 (BR 5020003130264); DR CONGO, Upper Katanga Province, near Kisangwe, Mikembo sanctuary, 11°28.790'S, 27°40.367'E, 2 Feb. 2012, 1170 m a.s.l., miombo woodland with Julbernardia globiflora (Benth.) Troupin and Brachystegia spp, De Kesel 5026 (BR 5020212174363V); MALAWI, Nkhata bay district, Chisosira, 16 miles south of Chinteche, 3 Jan. 1978, woodland with Brachystegia spiciformis Benth., 450 m a.s.l., E. Tybaert 141 (BR 5020019389861, dupl. GENT); MOZAMBIQUE, Nambula Province, Natala, Reserva de Mecuburi, 27 Jan. 2011, leg. M. Härkönen, Marja Härkönen 201131 (H 7016064); TOGO, Central Province, Kparatao (towards Bassar), 09°11.630'N, 0°59.134'E, 14 Jul. 2007, 580 m a.s.l., miombo woodland with Uapaca togoensis and Monotes kerstingii Gilg., De Kesel 4359 (BR 5020163710719, duplicate in TOGO); ZIMBABWE, Midlands Province, Mtao Forest, 19°22.081'S, 30°40.383'E, 11 Feb. 1999, 1500 m a.s.l., extensively grazed miombo woodland, under Brachystegia spiciformis , De Kesel 2453 (BR 5020112623060).

Ethnomycological data.

except for Mozambique and Zimbabwe, no local names or uses were collected. The local name in Mozambique (in Makua) is Ettuli ya Khapa (coll. Marja Härkönen 201131), which means tortoise shell. The local name in Zimbabwe (in chiShona) is dindindi java ( Sharp 2011). The species is not used for consumption.