Research Article |
Corresponding author: André De Kesel ( andre.dekesel@botanicgardenmeise.be ) Academic editor: María P. Martín
© 2018 Sylvestre A. Badou, André De Kesel, Olivier Raspé, Martin K. Ryberg, Atsu K. Guelly, Nourou S. Yorou.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Badou AS, De Kesel A, Raspé O, Ryberg MK, Guelly AK, Yorou NS (2018) Two new African siblings of Pulveroboletus ravenelii (Boletaceae). MycoKeys 43: 115-130. https://doi.org/10.3897/mycokeys.43.30776
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This paper sorts out the taxonomy of species affiliated with Pulveroboletus ravenelii in the Guineo-soudanian and Zambezian woodlands of Africa. Morphological and genetic characters of African Pulveroboletus collections were studied and compared to those of North American and Asian species. A phylogenetic analysis showed that the African specimens form a subclade, sister to the Asian and American taxa. Although clamp connections have previously never been reported from Pulveroboletus, all specimens of the African subclade show very small clamp connections. Two new African species, Pulveroboletus africanus sp. nov. and P. sokponianus sp. nov., are described and illustrated. Comments concerning morphology and identification, as well as distribution and ecology, are given for both species.
Boletales , Africa, Pulveroboletus , morphology, phylogeny, taxonomy
Boletes belonging to Pulveroboletus Murrill are morphologically characterised by boletoid basidiomata with a pulverulent arachnoid veil. As originally indicated by
Specimens were obtained from our own fieldwork or from herbarium specimens at our disposal. Protocols for field collecting, macroscopic description, drying and preservation follow
Genomic DNA was isolated from CTAB-preserved tissues or dry specimens using a CTAB isolation procedure adapted from
Sequences of Pulveroboletus species, including the type species P. ravenelii, along with sequences of various genera of the Pulveroboletus group (
List of collections used for DNA analyses, with origin, GenBank accession numbers and references.
Species | Voucher | Origin | atp6 | tef1 | rpb2 | Reference |
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Baorangia pseudocalopus | HKAS63607 | China | – | KF112167 | KF112677 |
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Baorangia pseudocalopus | HKAS75739 | China | – | KJ184570 | KM605179 |
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Butyriboletus appendiculatus | VDKO0193b | Belgium | MG212537 | MG212582 | MG212624 |
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Butyriboletus pseudoregius | VDKO0925 | Belgium | MG212538 | MG212583 | MG212625 |
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Butyriboletus pseudospeciosus | HKAS63513 | China | – | KT990743 | KT990380 |
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Butyriboletus roseoflavus | HKAS54099 | China | – | KF739779 | KF739703 |
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Butyriboletus roseopurpureus | BOTH4497 | USA | MG897418 | MG897428 | MG897438 |
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Butyriboletus subsplendidus | HKAS50444 | China | – | KT990742 | KT990379 |
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Butyriboletus cf. roseoflavus | OR230 | China | KT823974 | KT824040 | KT824007 |
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Caloboletus calopus | ADK4087 | Belgium | MG212539 | KJ184566 | KP055030 |
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Caloboletus inedulis | BOTH3963 | USA | MG897414 | MG897424 | MG897434 |
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Caloboletus radicans | VDKO1187 | Belgium | MG212540 | MG212584 | MG212626 |
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Caloboletus yunnanensis | HKAS69214 | China | – | KJ184568 | KT990396 |
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Cyanoboletus brunneoruber | OR0233 | China | MG212542 | MG212586 | MG212628 |
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Cyanoboletus pulverulentus | RW109 | Belgium | KT823980 | KT824046 | KT824013 |
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Cyanoboletus sp. | OR0257 | China | MG212543 | MG212587 | MG212629 |
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Lanmaoa angustispora | HKAS74752 | China | – | KM605154 | KM605177 |
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Lanmaoa asiatica | HKAS63603 | China | – | KM605153 | KM605176 |
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Lanmaoa carminipes | BOTH4591 | USA | MG897419 | MG897429 | MG897439 |
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Neoboletus brunneissimus | HKAS50538 | China | – | KM605150 | KM605173 |
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Neoboletus brunneissimus | OR0249 | China | MG212551 | MG212595 | MG212637 |
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Neoboletus junquilleus | AF2922 | France | MG212552 | MG212596 | MG212638 |
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Neoboletus magnificus | HKAS54096 | China | – | KF112149 | KF112654 |
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Neoboletus venenatus | HKAS63535 | China | – | KT990807 | KT990448 |
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Pulveroboletus africanus (type) | ADK4650 | Togo | KT823959 | KT824025 | KT823992 |
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Pulveroboletus brunneopunctatus | OR0147 | China | MG897420 | MG897430 | MG897440 |
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Pulveroboletus brunneopunctatus | HKAS55369 | China | – | KT990814 | KT990455 |
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Pulveroboletus brunneopunctatus | HKAS74926 | China | – | KT990815 | KT990456 |
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Pulveroboletus fragrans | OR0673 | Thailand | KT823977 | KT824043 | KT824010 |
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Pulveroboletus macrosporus | HKAS57628 | China | – | KT990812 | KT990453 |
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Pulveroboletus sokponianus (type) | ADK4360 | Togo | KT823957 | KT824023 | KT823990 |
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Pulveroboletus sokponianus | SAB0629 | Benin | MH983001 | MH983002 | MH983003 | This study |
Pulveroboletus ravenelii | REH2565 | U.S.A. | KU665635 | KU665636 | KU665637 |
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Pulveroboletus sp. | OR0282 | China | MK058515 | MK058518 | MK058521 | This study |
Pulveroboletus sp. | OR0644 | Thailand | MK058516 | MK058519 | MK058522 | This study |
Pulveroboletus sp. | OR0686 | Thailand | MK058517 | MK058520 | MK058523 | This study |
Retiboletus fuscus | OR0231 | China | MG212556 | MG212600 | MG212642 |
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Retiboletus griseus | MB03-079 | U.S.A. | KT823964 | KT824030 | KT823997 |
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Rhodactina rostratispora | SDBR-CMU-SV208 | Thailand | MG212561 | MG212606 | MG212646 |
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Rubroboletus legaliae | VDKO0936 | Belgium | KT823985 | KT824051 | KT824018 |
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Rubroboletus rhodosanguineus | BOTH4263 | USA | MG897416 | MG897426 | MG897436 |
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Rubroboletus satanas | VDKO0968 | Belgium | KT823986 | KT824052 | KT824019 |
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Rubroboletus sinicus | HKAS56304 | China | – | KJ619483 | KP055031 |
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Rugiboletus brunneiporus | HKAS83209 | China | – | KM605144 | KM605168 |
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Rugiboletus extremiorientalis | HKAS76663 | China | – | KM605147 | KM605170 |
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Rugiboletus extremiorientalis | OR0406 | Thailand | MG212562 | MG212607 | MG212647 |
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Suillellus luridus | VDKO0241b | Belgium | KT823981 | KT824047 | KT824014 |
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Suillellus subamygdalinus | HKAS53641 | China | – | KT990841 | KT990478 |
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Sutorius australiensis | REH9441 | Australia | MG212567 | JQ327032* | MG212652 |
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Sutorius eximius | REH9400 | U.S.A. | MG212568 | JQ327029* | MG212653 |
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The alignment contained sequences from 50 specimens and was 2,649 characters long (TreeBase number 23416). In the phylogram obtained (Fig.
Maximum likelihood phylogenetic tree inferred from the three-gene dataset (atp6, rpb2, tef1), including Pulveroboletus africanus sp. nov. and Pulveroboletus sokponianus sp. nov and selected Boletaceae. The three Leccinoideae species (Retiboletus fuscus (Hongo) N.K. Zeng & Zhu L. Yang, R. griseus (Frost) Manfr. Binder & Bresinsky and Rhodactina rostratispora S. Vadthanarat, O. Raspé & S. Lumyong) were used as outgroup taxa. Bootstrap frequencies > 70% are shown above supported branches.
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).
Epithet refers to its very wide distribution throughout tropical Africa.
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.
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).
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 (
Togo, Central Province, Kparatao (towards Bassar), 09°11.630'N, 0°59.134'E, 14 July 2007, alt. 580 m, woodland on a slope with Isoberlinia doka, Uapaca togoensis and Monotes kerstingii, leg. A. De Kesel, De Kesel 4360 (BR!, BR 5020163695566, duplicate in TOGO).
in honour of the late Prof. Dr. Ir. Nestor Sokpon, esteemed colleague of the University of Parakou (Benin), for his various contributions to the understanding of woodland ecology and regeneration.
Basidiomata medium-sized, wrapped in a greenish-yellow (1A2–3) general veil when young. Pileus 40–55(60) mm diam., at first hemispherical to convex, then pulvinate or plano convex, upper layer pale yellow (1A2–4) to greenish-grey (1BC3–4), not cyanescent, dry, mat, tomentose to felty, becoming subtly to inconspicuously cracked, greenish-yellow (1A2–3) in the deeper layers; scales subtle, flat, slightly felty, greenish-grey (1BC3–4), darker in the centre, diffused towards the margin; margin at first incurved, appendiculate with age, greenish-yellow. Hymenophore tubulate, separable, straight to slightly sinuate, depressed around the stipe; tubes up to 7 mm long, yellow to greyish-yellow (1B3), cyanescent when cut; pores regular, mostly round or slightly angular, slightly elongated around the stipe, small (13–16/mm), pale yellow (1A2–2A2), cyanescent. Stipe cylindrical, 42–60 × 6–7(9) mm, central, solid, uppermost part yellowish-white (1A2–3), smooth, lower part sheathed with a mat, dry, fibrillose-cottony, thick, yellowish-white to pale yellow (1A2–4) or pale greenish-grey (1BC3–4) layer, the latter rather tearing than cracking in subtle fibrils; ring at first woolly, cottony, pale greenish-yellow (1A2–4), then collapsing, leaving diffuse remains on pileus margin and stipe, sometimes pulverulent. Context whitish to whitish-yellow in the pileus, gradually yellowish-white (1A2) towards the base of the stipe. Slightly and slowly cyanescent, except in the base of the stipe. Basal mycelium and rhizomorphs usually white. Odour fungoid, when fresh like Lepista nuda (in collection De Kesel 1979). Spore print and macrochemical reactions not obtained.
Spores (8.5–)8.5–9.3–10.2(–10.5) × (4.4–)4.3–4.9–5.4(–5.6) µm, Q = (1.76)1.74–1.92–2.1(–2.14), broadly ellipsoid, smooth, pale yellowish-brown in 5% KOH and Melzer’s reagent, thin-walled, inamyloid. Basidia 4-spored, 21–32 × 8–12 µm, clavate, hyaline, sterigmata 3–4 µm long, without clamp connection. Cheilocystidia abundant, fusiform to clavate, (36.8–)34.1–42.7–51.4(–52.8) × (6.6–)7.7–9.7–11.7(–11) µm, thin-walled, with yellow intracellular pigment (persistent in NH4OH). Pleurocystidia similar to cheilocystidia, not abundant. Hymenophoral trama divergent, with regular mediostratum. Pileipellis a tomentum, composed of irregularly intertwined hyphae of similar shape, cylindrical, 3.3–5.1(6.2) µm wide, entirely hyaline, smooth, with small clamps. Stipitipellis a tomentum composed of elements similar to the pileipellis. Partial veil with cylindrical hyphae, 3–6 µm wide, thin-walled, smooth. Clamp connections small, frequent in the pileipellis.
BENIN, Atacora Province, Natitingou, Kota falls, 10°12.680'N, 1°26.723'E, 23 Aug. 1997, 520 m a.s.l., savannah woodland with Isoberlinia, A. De Kesel 1979 (BR 5020074831442); ibidem, 10°12.555'N, 001°26.793'E, 26 Jun. 2004, 480 m a.s.l., forest gallery with Berlinia grandiflora and Uapaca sp., A. De Kesel 3769 (BR 5020152060610); ibidem, Kouandé, 10°17.159'N, 1°40.890'E, 25/09/2000, 470 m a.s.l., savannah woodland with Isoberlinia tomentosa (Harms) Craib & Stapf, A. De Kesel 2942 (BR 5020129153468); ibidem, Borgou Province, Doguè, 9°07.249'N, 1°54.839'E, 10/10/2001, 350 m a.s.l., savannah woodland with Afzelia africana S.M. and Isoberlinia doka, A. De Kesel 3213 (BR 5020149693227); ibidem, Borgou Province, Okpara, 9°14.669'N, 2°43.377'E, 9 Aug. 2017, 360 m a.s.l., savannah woodland with Isoberlinia doka, S. Badou 0629 (UNIPAR); ibidem, Tamarou (forêt classée de N’dali), 9°44.680'N, 2°41.544'E, 31 Jul. 2017, 390 m a.s.l., savannah woodland with Isoberlinia doka, S. Badou 0624 (UNIPAR); ibidem, 4 Aug. 2017, 390m a.s.l., S. Badou 0625 (UNIPAR); ibidem, Wako, 9°09.457'N, 2°05.599'E, 11/09/2001, 300 m a.s.l., savannah woodland with Isoberlinia doka, Uapaca togoensis and Burkea africana Hook., A. De Kesel 3132 (BR 5020149809413); ibidem, Wari Maro, 9°10.038'N, 2°09.931'E, 20 Aug. 1997, 310 m a.s.l., savannah woodland with Isoberlinia doka, A. De Kesel 1943 (BR 5020074934501); ibidem, 9°09.884'N, 2°09.595'E, 22 Jun. 1998, 310 m a.s.l., savannah woodland with Isoberlinia doka, A. De Kesel 2183 (BR 5020112693766); ibidem, 9°08.110'N, 2°10.215'E, 09/10/2001, 290 m a.s.l., savannah woodland with Isoberlinia doka and Uapaca togoensis, A. De Kesel 3188 (BR 5020149726550); ibidem, 9°09.900'N, 2°09.511'E, 23/09/2001, 310 m a.s.l., savannah woodland with Isoberlinia doka and Uapaca togoensis, A. De Kesel 3237 (BR 5020149751804); ibidem, 9°10.027'N, 2°10.848'E, 16 Jun. 2002, 340 m a.s.l., savannah woodland with Isoberlinia doka and Uapaca togoensis, A. De Kesel 3411 (BR 5020152133376); ibidem, Collines Province, Toui-Kilibo, 8°32.746'N, 2°40.424'E, 19 Jul. 2017, 320 m a.s.l., savannah woodland with Isoberlinia doka and I. tomentosa, S. Badou 0519 (UNIPAR); ibidem, 5 Jul. 2017, S. Badou 0617 (UNIPAR); ibidem, 13 Jul. 2017, S. Badou 0621 (UNIPAR); ibidem, Donga Province, Bassila, 8°57.319'N, 1°38.391'E, 14 Jun. 2002, 380 m a.s.l., savannah woodland with Berlinia grandiflora, A. De Kesel 3403 (BR 5020152245529); ibidem, 8°59.516'N, 1°38.261'E, 26 Jun. 2002, 370 m a.s.l., gallery forest with Berlinia grandiflora, Elaeis guineensis Jacq. and Raphia sp., A. De Kesel 3467 (BR 5020152045464); ibidem, 9°0.073'N, 001°39.318'E, 17 Jun. 2004, 380 m a.s.l., gallery forest with Berlinia grandiflora, A. De Kesel 3668 (BR 5020157041959); ibidem, Penessoulou (south), 9°9.688'N, 1°34.793'E, 4 Jul. 2017, 380 m a.s.l., small gallery forest with Isoberlinia doka, S. Badou 0613 (UNIPAR); ibidem, 11 Aug. 2017, S. Badou 0630 (UNIPAR); ibidem, 22 Aug. 2017, S. Badou 0631 (UNIPAR); ibidem, Zou Province, Ouèssè, Gbadji forest (West side of the slope), 7°57.152'N, 001°58.095'E, 13 Jun. 2004, 310 m a.s.l., savannah woodland with Isoberlinia doka, Burkea africana, A. De Kesel 3593 (BR 5020157206662). TOGO, Central Province, Fazao (Parc National), 08°42.150'N, 0°46.383'E, 16 Jun. 2011, 520 m a.s.l., savannah woodland with Afzelia africana, A. De Kesel 4910 (BR 5020212173335V); ibidem, 08°43.963'N, 0°47.674'E, 16 Jul. 2007, 510 m a.s.l., savannah woodland with Isoberlinia doka and Uapaca togoensis, A. De Kesel 4382 (BR 5020163713741); ibidem, 08°38.737'N, 0°46.010'E, 17 Jul. 2007, 550 m a.s.l., gallery forest with Berlinia grandiflora, A. De Kesel 4393 (BR 5020163839069); ibidem, 08°43.145'N, 0°46.332'E, 20 Jul. 2007, 560 m a.s.l., savannah woodland on gravelly soil, with Uapaca togoensis, A. De Kesel 4469 (BR 5020163803671); ibidem, 08°40.872'N, 0°45.487'E, 04 Jun. 2008, 680 m a.s.l., savannah woodland with Isoberlinia doka and Uapaca togoensis, A. De Kesel 4625 (BR 5020165412277).
Except for Benin, no local names or uses were collected. The local name in Nagot language is osousou eti (coll. De Kesel 2183) and this species is not eaten.
The African collections represent two separate species, Pulveroboletus africanus sp. nov. and P. sokponianus sp. nov., both macroscopically similar to Pulveroboletus ravenelii. In the latter, however, the disc becomes reddish-orange to reddish-brown at maturity and it grows in temperate conifer woods (
Macroscopically, both African taxa can be distinguished based on the colour of the scales on the pileus and the stipe, being brown in P. africanus and greenish-grey or yellow in P. sokponianus. In P. africanus, the basal mycelium and context in the base of the stipe is generally yellow whereas it is whitish to whitish-yellow in P. sokponianus. While bluing of the context depends on the freshness and the maturity of the basidiomes, it seems more pronounced in P. africanus. Although cystidia have been reported to be rather constant and of little use to separate Asian taxa (
Young basidiomes of Pulveroboletus sokponianus are strongly reminiscent of the Asian P. brunneopunctatus G. Wu & Zhu L. Yang, but the latter has a viscid veil and smaller cheilocystidia. Using the key of the Chinese species (
Both new species are endemic to tropical Africa. Pulveroboletus africanus was found in Benin, Burundi, Guinea, DR Congo, Malawi, Mozambique, Togo, Zimbabwe and possibly also Zambia. It prefers regions with a pronounced wet/dry season alternance and occurs in a wide variety of woodlands, savannah woodlands and gallery forests across tropical Africa. It seems absent in the dense rainforests (Congolian region). The species is terricolous and most probably ectomycorrhizal (EcM), occurring in EcM dominated forests up to 1500 m elevation. It is difficult to ascertain if the species associates with Caesalpiniaceae (Berlinia, Brachystegia, Isoberlinia, Julbernardia) and/or with Uapaca (Phyllantaceae). Only Uapaca is well represented throughout its distribution range. In Eastern Africa (Zambezian region), it is also found under Brachystegia spp. and Julbernardia spp.; in West Africa (Soudano-Guinean region) under Berlinia grandiflora and Isoberlinia spp.,
Pulveroboletus sokponianus has so far only been found in a variety of savannah woodlands and gallery forests in the Soudano-Guinean transition zones of Benin and Togo, probably also in Ivory Coast (see fig. 3a in Léabo et al. 2017). The species is terricolous, most probably ectomycorrhizal (EcM) and most often found under Isoberlinia doka (Caesalpiniaceae). Since habitat destruction and felling of host trees is common practice in Benin,
Badou S. and Guelly A.K. acknowledge the Belgian focal point for the Global Taxonomy Initiative (CEBioS programme) for research grants at Meise Botanic Garden (Belgium) and support for fieldwork in Togo, respectively. Badou S., Yorou N.S. and M. Ryberg are grateful to FORMAS (Sweden) for financially supporting part of the fieldwork in Benin (grant 226-2014-1109). Badou S. and Yorou N.S. thank the Volkswagen Foundation (grant 90-127), Meise Botanic Garden and the Global Taxonomy Initiative (CEBioS programme) for financing or supplying laboratory equipment to the University of Parakou (Benin).
De Kesel A. acknowledges grants and logistic support from MIKEMBO and BAK (Biodiversité au Katanga) for supporting the fieldwork in DR Congo (2012–2018). He acknowledges the King Léopold III Fund for Nature Exploration and Conservation, as well as the Foundation to Promote Scientific Research in Africa for financially supporting fieldwork in Benin (2002, 2004) and in Togo (2007, 2008, 2011).
We express our gratitude to Daniel Thoen (Belgium), Jan Rammeloo (Belgium), Marja Härkönen (Finland), Maba Dao (Togo), Bill Kasongo, Michel Hasson, Michel Anastassiou (DR Congo), Anxious Masuka (Zimbabwe), André De Groote (Benin) and Jean Claude Codjia (CECODI, Benin) for kindly providing specimens or help and logistic support during our fieldwork. Wim Baert and Myriam de Haan are acknowledged for assistance in the molecular lab of Meise Botanic Garden. We thank Roy Halling for indicating additional references.