Tree 8–45 m tall, d.b.h. 10–125 cm. Young branches at first sparsely pubescent, later glabrous, trichomes 0.2–0.8 mm long, erect; old branches glabrous. Leaves: petiole 2–8 mm long, 1.0–2.5 mm in diameter, pubescent to glabrous, trichomes 0.3–0.8 mm long, indumenta brown; lamina 5.1–15.6 cm long, 2.0–6.7 cm wide; length:width ratio 1.5–4.0; elliptic to narrowly elliptic, base rounded or cuneate, apex acuminate, apiculate, aristate or caudate, acumen 6–14 mm long, upper side glabrous, lower side densely to sparsely pubescent; midrib upper side basely sparsely pubescent, lower side densely to sparsely pubescent, trichomes 0.4–0.8 mm long; secondary veins 5–12 pairs, upper side glabrous, lower side pubescent to sparsely pubescent, trichomes 0.3–0.8 mm long; tertiary veins irregularly prominent, slightly raised or indistinct above. Inflorescence 1–4 flowered per rhipidium. Floral buds ellipsoid, 4–8 mm long, 3.0–4.6 mm in diameter, densely pubescent. Flowers, flowering pedicel 3.0–6.3 mm long, 0.8–2.1 mm wide, trichomes ca. 0.5 mm long, bract 1.4–3.1 mm in diameter, pubescent, trichomes 0.4–0.5 mm long. Sepals 1.8–3.8 mm long, 2.1–3.9 mm wide, length:width ratio 0.5–0.9 broadly ovate, apex acuminate, base truncate, outside pubescent, inside sparsely pubescent towards the centre, trichomes 0.1–0.5 mm long. Inner and outer petals 8–18 mm long, 1.3–2.6 mm wide, length: width ratio 0.7–0.9, narrowly ovate, to narrowly elliptic, apex acuminate, base rounded, outside pubescent, trichomes 0.2–0.5 mm long tomentose, erect, inside sparsely pubescent to glabrous, glabrous part to 2.0–4.1 mm long green maturing pale yellow. Male flowers: stamens 16–25, in several whorls, 2–4 mm long, 0.4–0.8 mm wide, tightly appressed; connectives tongue-shaped; hermaphrodite flowers: stamens 5–10 in a single whorl, appressed, 0.9–2.2 mm long and 0.3–0.8 mm wide, connective tongue-shaped; carpels 12–20, 0.7–1.6 mm long, 0.5–0.8 mm wide, length:width ratio 2.3–2.7 oblong, densely pubescent; ovules 1–2, oblong; stigmata ovoid, densely pubescent, trichomes ca. 0.5 mm long. Fruiting pedicel 5.5–12.0 mm long, 1.5–2.5 mm wide, sparsely pubescent, trichomes ca. 0.5 mm long; stipes 4.5–10.0 mm long and 1.0–2.5 mm wide, sparsely pubescent; monocarps 2–8, 7.2–16.4 mm in diameter, broadly ellipsoid to globose, sparsely pubescent to glabrous, green turning wine red at maturity; seeds 1–4 per monocarp, 3.0–11.2 mm in diameter, ellipsoid to globose, flattened when more than one seed per monocarp, surface covered by a white tegument.

Widespread across Central Africa, in Nigeria, Cameroon, Republic of Congo, Gabon, Equatorial Guinea (Rio Muni), Central African Republic, Uganda, São Tomé-and-Prìncipe, Democratic Republic of the Congo, Angola (Cabinda) (Fig. 11).

Moist evergreen and semi-deciduous lowland and mid-altitude 30–1600 m in forests.

In Gabon and southwest Cameroon, flowering from January to April. Fruits are mature from November to December.

Cameroon: Moabé noir (Nzime), Otunga (Fang), Otungui (Ewondo) Ntoulen (bassa), Botounga (Baka). Gabon: Mutunga (Aduma, Awandji and Nzebi), Otunga (Fang, Kota and Obamba). Democratic Republic of Congo: Yako-Ledale, Babua Embaye, Bombai Bo Ilo (Turumbu), Mwamba (Kiumba), Moamba Ndombe, Bombaye, Djako-Ledale. Central African Republic: Modienge (Lissango), Motunga. Nigeria: Nchua (Bokyi), EDO Ewáé (Edo), Eleku (Isekiri) okeren (Kennedy) Atorewa (Urhobo), agudugbu (Yoruba).

The wood of Greenwayodendronsuaveolens is used for carpentry and construction of habitats, but also for the manufacture of hunting and fishing spears (Le Thomas 1969). Bark decoctions are used as a laxative to facilitate childbirth and as a stimulant for women’s fertility in the Republic of Congo (Boutique 1951). In Cameroon and Gabon, bark ash is rubbed in scarifications, on the forehead to treat psychosis and bark paste is applied externally to treat rheumatism, headache, epilepsy, toothache and malaria (Le Thomas 1965, Raponda-Walker and Silians 1961). In the Democratic Republic of Congo, decoctions of the bark are used to calm colic. In Nigeria, the leaf has been recorded as being taken internally for menorrhagia.

Least Concern [LC]. The extent of occurrence (EOO) of Greenwayodendronsuaveolens is estimated to be over 2,316,419 km², whereas its area of occupancy (AOO) is estimated to be 476 km² (which falls within the limits for Vulnerable status under criterion B2). The species, recorded from 10 countries (Nigeria, Cameroon, Republic of Congo, Gabon, Equatorial Guinea (Rio Muni), Central African Republic, Uganda, Sao Tome and Principe, Democratic Republic of Congo and Angola (Cabinda)), is now known from at least 126 specimens representing 88 subpopulations. These 88 subpopulations represent 93 different locations (sensu IUCN 2012), many more than 10 locations, which are the upper limit for Vulnerable status under subcriterion ‘a’. Greenwayodendronsuaveolens has been collected in 13 protected areas in the following countries: Nigeria, Cameroon, Republic of Congo, Gabon, Equatorial Guinea (Rio Muni), Central African Republic, Uganda, São Tomé-and-Prìncipe, Democratic Republic of the Congo, Angola (Cabinda). The main threat to G.suaveolens is its habitat destruction resulting from urbanisation in Central Africa as well as intensive agriculture and mining in the Democratic Republic of Congo. Notwithstanding these human activities, with varying levels of impact, the species appears not as threatened as it is abundant. The available information suggests that the number of subpopulations and mature individuals of G.suaveolens, as well as its EOO and AOO, will not decrease noticeably in the next ten years.

In Gabon, G.suaveolens and G.gabonicum occupy the same habitat (mature tierra firme forest) and can occur in sympatry. However, G.gabonicum has a clearly tomentose pubescence of the lower face of the lamina which is sparsely pubescent in G.suaveolens.

In the original description of P.? acumianata, Oliver cited two syntypes (Mann 841 and Thomson 109). However, both represent different species (Verdcourt 1969). The former is the type species of G.oliveri and the latter a specimen of G.suaveolens.

We lectotypified the type specimen of G.suaveolens, as the specimen H. Soyaux 218 from Berlin is thought to have been destroyed. In describing Polyalthiamortehani, De Wildeman (De Wildeman, 1914) did not designate a type specimen. The observation of the two specimens present in BR (Mortehan 362; De Giorgi 1576), led us to select the sample De Giorgio 1576 as the lectotype because it contains the best flowers’ information.

In their description of Polyalthiaoliveri, Engler and Diels (1901) identified the Zenker G.A. specimens from Cameroon as P.oliveri. In the Flore Forestière de la Côte d’Ivoire (1936), Aubréville indicates that these Zenker specimens are not P.oliveri and introduces the name P.aubrevillei (now a synonym of G.suaveolens). He refers to the illustration of Engler and Diels (1901) of P.oliveri as being Polyalthiaaubrevillei. He provided a key to separate both species (P.oliveri and P.aubrevillei) with “Etamines à connectif très allongé aigu” [Stamens with very long and acute connective] for P. aubrévillei. Following the code (Art. 38.13, McNeill et al. 2012), this description is valid because it contains a diagnose (the key) and was published prior to 1953 validating the direct reference of a previous description for the specimens belonging to this new name. Based on the specimens cited by Engler and Diels (1901) from Cameroon, we selected Zenker 1306 as the lectotype because it contains numerous opened flowers.

Finally, it must be noted that analyses of morphology and genetic diversity (Lissambou et al. in press) identified a group of specimens collected in São Tomé and Prìncipe as possibly distinct. However, to date, the status of this group of specimens is inconclusive, partly related to the lack of fertile material.

Angola. Luali – Buco Zan: Ponga Mungo-Subluali, 4°39.10'S, 12°46.10'E, 14 Feb 1916, J. Gossweiler. 6275 (COI); Maiombe – Subluali, 4°39.11'S, 12°46.15'E, 31 Sep 1916, J. Gossweiler 6229 (COI); Ponga Mungo – Subluali Maiombe, 14 Jan 1916, J. Gossweiler 6145 (COI).

Cameroon. Central: 2 km NW of Ossoéssam (Village among Rhaphia) about 40 km SSW Of Mbalmayo, 3°25'N, 11°30'E, 1 Apr 1965, Leeuwenberg, A.J.M. 5755 (BR, P); 41 km from the LBC Eseka sawmill, 3°39'N, 10°46'E, 14 Feb 1953, Mpom, B. 74 (P, YA); Forêt classée de Mbalmayo, 3°43'N, 9°59'E, 15 Nov 1970, Mpom, B. 537 (P, YA); Riverine forest. Bank Nyong Rivers, near the new bridge, about 65 km SSW of Eséka, 3°39'N, 10°46'E, 17 Jul 1964, Wilde, W.J.J.O. de. 2857 (BR; P). East region: Around the village of Mindourou I. UFA managed by Pallisco, 3°16.464'N, 13°23.01'E, 9 Nov 2012, Droissart, V. 1420 (BRLU); 15 E of Dimako, 4°21'N, 13°40'E, 11 Dec 1965, Leeuwenberg, A.J.M. 7322 (BR, P, WAG); Colline de l’ENE de Mbalam (140 km) of ESE Djoum, near Souanke-Congo, 2°13'N, 13°48'E, 20 Jan 1973, Letouzey, R. 11866 (P, YA, WAG); UFA 10039B Palisco Mindourou, 3°26.0712'N, 13°26.081'E, 12 Mar 2016, Lissambou, B.J. 2100 (BRLU). Littoral: 20 km from Kribi lumbering, 3°00'N, 10°03'E, 9 Jun 1970, Bos, J.J. 4769 (BR, P, YA, WAG); EDEA/Village Pout-loloma, 3°53.041'N, 10°8.824'E, 15 Jan 2016, Lissambou, B.J. 1725 (BRLU); EDEA/Village Pout-loloma, 16 Jan 2016, Lissambou, B.J. 1726 (BRLU). South Region: La lobé, 0°32'N, 12°46'E, 2 Dec 1927, Hedin 1943 (BR); Ebolowa-Ambam, 16 km on the road from Ebolowa to Minkok, 2°58'N, 11°17'E, 12 Sep 1975, Wilde, J.J.F.E de. 8465 (BR, YA, P); 13 km along the road from Kribi to Ebolowa. Raphia swamp with small creek in the middle, 2°52'N, 10°00'E, 26 Nov 1975, Wilde, J.J.F.E. de 8674 (P, YA, WAG); 10 km environ à l’ESE de Campo Kribi, 2°15'N, 9°60'E, 26 Mar 1968, Letouzey, R. 9198 (YA, P); Parc Campo MA’AN. Mature primary forest, 2°17.424'N, 9°56.893'E, 18 Jan 2016, Lissambou, B.J. 1795 (BRLU); Nkomekak, 2°46.990'N, 10°31.858'E, 5 Feb 2016, Lissambou, B.J. 1900 (BRLU); Bipendi. Urwaldgebiet, 3°40'N, 10°24'E, 1900, Zenker, G.A. 2166 (YA, P, WAG); Bipendi. Urwaldgebiet, 3°40'N, 10°34'E, 1912, Zenker, G.A. 4435 (P, WAG). South West region: Near Ngombombeng village, north of Nyasoso, 4°54'N, 9°42'E, 31 Apr 1986, Etuge, M. 30 (P, U, YA); Mile 12 Mamfé road between Kumba and Baduma, 4°45'N, 9°29'E, 4 Oct 1986, Nemba, J. 291 (P, WAG).

Central African Republic. Sangha-Mbaéré: Réserve de Dzanga-Sangha. Lowland forest, 2°22'N, 16°10'E, 14 Oct 1988, David, J. 1414 (BR); Grima (Commun de Ngotto), 3°54'N, 17°13'E, 11 Mar 1999, Yangakola, J.M. 153 (BRLU); Ngotto, 3°54'N, 17°13'E, 26 Jul 1994, Yalibanda, Y. 94/36 (BRLU). Lobaye: Boukoko, forest, 3°43'N, 17°46'E, 7 Oct 1948, Tisserant, C. 1172 (BR, P); Boukoko, 3°43'N, 17°46'E, 25 Aug 1953, Tisserant, R.P. 2573 (P).

Democratic Republic of the Congo. Kantanga: Kiobo, 5°38'S, 13°07'E, 2 Apr 1944, Donis, C. 84 (BR). Kasaï-Oriental: South o Booke (Terre, Kolo), 2°33'S, 22°00'E, May 1958, Robin, R. 90 (BR); Dundusana, Lekimi, 2°53'N, 22°23'E, Dec 1913, Mortehan 362 (BR). Orientale: Luki, vallée N’tosi, 5°38'S, 13°04'E, 14 Jul 1948, Donis, C. 1916 (BR); Yangambi, 0°46'N, 24°27'E, May 1937, Gilbert 96 (BR, P); Yangambi, Réserve flore Isalowe, 0°44'S, 24°27'E, 19 Aug 1938, Louis, J. 10916 (MO, P).

Equatorial Guinea. Rio Muni, Cento-Sur: Mont Alén, 1°30'N, 10°04'E, 16 Jun 1998, Ngomo, D. 342 (BRLU, MO); SO National Monte Alen Park, 200 m S of transct Ecofac of Mosumo 1620 early layon, 1°35'N, 10°03'E, 10 Mar 2011, Senterre, B. 784 (BRLU, MO).

Gabon. Estuaire: Brigade forestière d’Ekouk (nouvelles parcelles), 15 km north of Koulounga, 0°45'N, 9°50'E, 22 Sep 1983, Floret, JJ. 1389 (LBV, WAG); S of Ekouk, 0°6'S, 10°20'E, 2 Nov 1983, Louis, A.M. 308 (LBV, WAG); Forest exploitation Leroy, in road construction area, 0°57'S, 10°52'E, 19 Jan 1983, Wilde, J.J.F.E. 73 (LBV, WAG, U); Crystal Mountains, 0°53'S, 10°12'E, 20 km NW of Asok, Closed high forest in hilly country, 20 Jan 1983, Wilde, J.J.F.E. 101 (LBV, WAG, P). Moyen-Ogooué: Mabounié, 45 km southwest of Lambaréné, north bank of the Ngounié River, 0°28.854'S, 10°18.846'E, 13 Nov 2013, Bidault, E. 1297 (BRLU, LBV, MO). Ngounié: ibid. loc., 0°26.706'S, 10°19.458'E, 13 Oct 2012, Bidault, E. 798 (BR, BRLU, LBV, MO); Parc National de Waka, 1°06'S, 11°09'E, 7 Oct 2007, Boussiengui Nongo, J. 259 (LVB); Between Mouila to Yeno about 60 km from Mouila, 1°44'S, 11°24'E, 21 Sep 1986, Breteler, F.J. 8086 (BR, LBV, WAG); Massif du Chaillu, north-east of Mouila, Leroy shipyard, 1°40'S, 11°15'E, 24 Apr 1989, McPherson, G.D. 13907 (BR, P). Nyanga: Chantier CEB, ca. 45 km SW of Doussala, 2°35'S, 10°34'E, 22 Oct 1985, Reitsma, J.M. 1737 (LBV); Kwassa. Fishing village next to Banio Lagune, 3°23'S, 11°55'E, 13 May 2001, Walters, G.M. 656 (LBV). Ogooué-Ivindo: Makande surroundings, ca. 65 km SSW of Booué, 0°41'S, 11°55'E, 9 Feb 1999, Breteler, F.J. 14970 (LBV); Station de Recherche de l’Institut de Recherche en Ecologie tropicale (IRET-Ipassa), 0°29.808'N, 12°46.961'E, 1 May 2015, Lissambou, B.J. 1299 (BRLU, LBV, MO); Réserve de la Lopé, south of Ayem, site SOFORGA, 00°25'S, 11°30'E, 10 Mar 1989, McPherson, G.D 13748 (LBV); 25 km NE of Booué, 0°00'S, 12°20'E, 19 May 1987, Wilks 1544 (MO, P). Ogooué-Lolo: ca. 30 km E of Lastoursville, 0°40'S, 13°00'E, 20 Nov 1991, Breteler, F.J. 10611 (LBV); Forêt des Abeilles; 9 km S of Confluence Gongue-Offoue, 0°48'S, 11°45'E, 28 Jun 1996, Wilks, C.M. 2695 (WAG); Région de Lastoursville, 0°49'S, 12°43'E, 12 Mar 1931, Le Testu M.G. 8698 (BR, P). Ogooué-Maritime: Mont Doudou, Campagne, 2°31'S, 10°33'E, 19 Sep 2000, Bourobou, H.P. 323 (LBV); Toucan, edge road, 1°47'S, 9°53'E, 8 Jun 2002, Bourobou H.P. 704 (WAG); Lac Azingo. Grands lacs Moyen, 0°28.638'S, 10°1.992'E, 15 Oct 2014, Lissambou, B.J. 0011 (BR, BRLU, LBV, MO, P, WAG). Woleu-Ntem: ca. 25 km WSW of Mintsic, inventory Oveng, 0°44'N, 11°22'E, 9 Feb 1987, Reitsma, J.M. 2957 (LBV, WAG); ca 25 km WSW of Mintsic, Chantier Oveng, 0°44'N, 11°22'E, 9 Nov 1986, Reitsma, J.M. 2580 (LBV); Inselberg Milobo, 0°56'N, 10°30.9'E, 8 Jul 2001, Ngok Banak, L. 45 (LBV); Near Essong, ± 5 km NW of Mitzic, along exploitation road, 0°46'N, 11°27'E, 9 Nov 1991, Louis, A.M. 550 (LBV, P, WAG).

Nigeria. South Eastern State: Boshi extension Forest Reserve, 13°20'N, 9°20'W, 25 May 1971, Van Meer, P.P.C. 1795 (WAG); Forest Reserve of Enyong, 5°20'N, 7°50'W, 8 Apr 1971, Van Meer, P.P.C. 1228 (WAG). Western State: Abeokuta, 3°30'N, 7°25'W, Wit, P. 2111 (K).

São Tomé and Príncipe. Prìncipe: Alentours de Zona ecológica. Pico Papagaio (Zona ecológica), 1°36.75'N, 7°391'E, 26 Mar 1998, Oliveira F. de. 588 (BRLU, MO). São Tomé. Mé-Zochi: Bom Sucesso to Lagoa Amelia (site S.P, km 0,6), 0°7.02'N, 6°35'E, 4 Jul 1987, Lejoly, J. 97/362 (BRLU, MO); Base Pico Maria Fernandes, 0°10'N, 6°38'E, 27 Feb 2003, Ogonovszky, M. 293 (BRLU, MO); Lago Amelia, south of Bom Sucesso Botanical Garden, 0°16'N, 6°35'E, 11 Feb 2009, Dauby, G.1574 (BRLU, MO).

Republic of Congo. Kouilou: Forest site at 20 km N of Loundji Moyombe, 0°52'S, 14°49'E, 23 Mar 1969, Attims, Y. 115 (P); Douakani, 2°56.038'N, 13°8.975'E, Kamit, T 1015 (K); Road to Boungolo site, Kakamoeka (Point-Noir). Niari: Lepoutou, 2°47.895'S, 13°27.52'E, 25 Jun 2011, Mpandzou, A.L. 1104 (K).