Uvariodendron fuscum var. giganteum (R.E.Fr.) Dagallier & Couvreur, PhytoKeys 207: 423 (2022)

Dagallier, Leo-Paul M. J., Mbago, Frank M., Couderc, Marie, Gaudeul, Myriam, Grall, Aurelie, Loup, Caroline, Wieringa, Jan J., Sonke, Bonaventure & Couvreur, Thomas L. P., 2023, Phylogenomic inference of the African tribe Monodoreae (Annonaceae) and taxonomic revision of Dennettia, Uvariodendron and Uvariopsis, PhytoKeys 233, pp. 1-200 : 1

Uvariodendron fuscum var. giganteum (R.E.Fr.) Dagallier & Couvreur, PhytoKeys 207: 423 (2022)

Figs 20 , 21 , 23

≡ Uvaria gigantea Engl., Notizbl. Königl. Bot. Gart. Berlin 2: 292. 1899 (quoad specimens Zenker 108 and 698); Uva gigantea Kuntze, Deutsche Bot. Monatsschr. xxi. 173 (1903); Uvariodendron giganteum (Engl.) R.E.Fr., Acta Horti Berg. 10: 62 (1930). Type. Cameroon - Central Region • G.A. Zenker 108 (lectotype: P! (P00362654), designated by Couvreur et al. (2022); isolectotype: COI! (COI00004926); lectotype designed by Fries (1930) as B, but sheet destroyed), Yaoundé, Yaunde; 3°52'N, 11°31'E; alt. 800 m; 1895.

Description.

Young branches with long soft hairs producing a whitish appearance quickly falling off. Petiole 8-35 mm long, 3.5-8 mm wide. Leaf lamina 357-676 mm long, 84-225 mm wide, length:width ratio 2.5-4, base acute to rounded, apex acute to acuminate, surface below pilose to glabrous when young, glabrous when old; midrib pilose to glabrous below; secondary veins 22-33 pairs. Flower pedicel 0-7.5 mm long. Bracts 1 to 6, upper bract 16-22 mm long, 20-50 mm wide. Sepals 20-30 mm long, 16-26 mm wide. Outer petals 25-40 mm long, 17-30 mm wide. Inner petals 21-40 mm long, 17-29 mm wide, length:width ratio 1.1-1.5, broadly obovate to obovate. Carpels 50 to 100. Fruiting pedicel 9-15 mm long. Monocarps 6 to 24, 20-50 mm long, 11-25 mm wide, length:width ratio 1.7-3.8, cylindrical, curved, acuminate, slightly constricted between the seeds, puberulent, green to brown. Seeds 8-14 per monocarp, ca. 14 mm long, ca. 7 mm wide.

Distribution.

Element of the Lower Guinean Domain and Congolia Domain of the Guineo-Congolian Region: Cameroon, Democratic Republic of the Congo, Gabon.

Habitat and ecology.

Lowland to submontane mature or old secondary rain forests, on inundated soils or along streams or rivers. Altitude: 100-1300 m a.s.l.

Notes.

Ud. fuscum var. giganteum differs from the type variety in having young branches and petiole covered with long soft hairs producing a whitish appearance quickly falling off (vs. young branches and petiole sparsely pubescent to glabrous). Compared to the type variety, it has larger leaves (35.7-67.6 cm long and 8.4-22.5 cm wide, vs. 16-45 cm long and 4.3-11.8 cm wide), with generally more secondary veins (22 to 33 vs. 15 to 24), and flowers with generally greater sepals (20-30 mm long vs. 11-23 mm long) and more carpels (50 to 100 vs. 20 to 70) (Fig. 4 , Table 4 ). Most of these characters overlap and without the young branches covered with long soft hairs it can be hard to place some specimens in the var. Uvariodendron fuscum giganteum with certainty. The specimen Zenker 108, defined to be the type specimen by Fries (1930), was not found in B (lost or destroyed), so we made the duplicate from P as the lectotype and the duplicate from COI as the isolectotype ( Couvreur et al 2022).

Additional specimens examined.

Cameroon - Central Region • G.A. Zenker 698 (B), Yaoundé, Yaunde ; 3°52'N, 11°31'E; alt. 800 m; 04 Feb. 1895 • T.L.P. Couvreur 419 (MPU, WAG, YA), Mont Mbam Minkon, on trail, 5 km from Nkol Nyada village ; 3°58'04.91'N, 11°24'08.64'E; alt. 1000 m; 21 Mar. 2013 - East Region • T.L.P. Couvreur 1206 (MPU, WAG, YA), 60 km south of Yokadouma, 30 km after Ngato, 15 km after river. ALPICAM 'base de vie', then on forestry road starting 4 km before Masea village ; 3°09'55.18'N, 14°42'25.64'E; alt. 587 m; 05 Mar. 2019 • T.L.P. Couvreur 1229 (MPU, WAG, YA), 60 km south of Yokadouma, 30 km after Ngato, 15 km after river. ALPICAM 'base de vie', then 40 km on forestry road starting 4 km before Masea village . Coupe 4-4 of UFA 023; 3°05'08.17'N, 14°40'18.2'E; alt. 622 m; 08 Mar. 2019 - South Region • G.A. Zenker 1438 (L), Bipinde, Urwaldgebiet ; 3°05'N, 10°25'E; 1898 • M. Biholong 279 (P, YA), près d'Alati. Ancienne piste Alati - Mintom II; 2°11'44.45'N, 13°24'17.61'E; 17 Jan. 1975 - South-West Region • C. Doumenge 473 (L, MO, P) , Cameroon. Bakossi Mountains 1-8 Km NNE of Menyum Village; 5°01'N, 9°38'E; alt. 1000 m; 22 May. 1987 • P. Lane 501 (K, SCA, WAG, YA), Mt Kupe Division. Ndum. Forest trail 2 km south from Etube-Tape village ; 4°51'N, 9°42'E; alt. 1200 m; 02 Feb. 1995 • T.L.P. Couvreur 1057 (MPU, WAG, YA), Nyasoso village, on max's trail to Mt Kupe ; 4°49'27.88'N, 9°41'59.42'E; alt. 1227 m; 05 Apr. 2016 • T.L.P. Couvreur 512 (MPU, YA); Fako, on trail from Ekongo village, located 5 km before the entrance to Limbe, 7 km on secondary road. On flank of Mt Etinde. 100 m in Mont Cameroon National Park ; 4°04'19.23'N, 9°08'00.76'E; alt. 959 m; 16 Oct. 2013 • T.R. van Andel 3761 (MO, SCA, U, WAG), Bokwango. Trail to Mann's spring; 4°07'44'N, 9°11'26'E; alt. 1130 m; 21 Jun. 2001 . Democratic Republic of the Congo - Orientale • T.B. Hart 910 (WAG); Mambasa, Epulu , Zaire, Zone de Mambasa (Ituri); 1°25'N, 28°35'E; alt. 750 m; 23 Mar. 1989 . Gabon - Estuaire • T.-J. Klaine 1690 (P), Environs de Libreville ; 0°25'N, 9°27'E; 18 Oct. 1899 - Ogooué-Ivindo • N. Hallé 3156 (P), Bélinga; 1°05'N, 13°08'E; 12 Nov. 1964 • N. Hallé 430 (K, P), Bélinga, mines de fer, le long de la rivière Folley ; 1°07'N, 13°11'E; 12 Aug. 1966 • N. Hallé 549 (K, P), Bélinga, mines de fer; 1°08'N, 13°12'E; alt. 700 m; 16 Aug. 1966 .

Figures

Figure 4. Morphological continuum in Uvariodendron fuscum: traits comparison for var. Uvariodendron fuscum fuscum (fusc.), var. Uvariodendron fuscum giganteum (gig.) and var. Uvariodendron fuscum magnificum (mag.). Each point represents a measurement. Vertical bars span the minimum and maximum values of the focal traits. Photos, left: leaf of Couvreur 1046; top right: flower, below view, of Couvreur 1046; below right: flower, top view, of Couvreur 990 (CC BY-NC 4.0 Thomas Couvreur).

Figure 20. Uvariodendron fuscum var. giganteum (R. E. Fr.) Dagallier & Couvreur A young branch with leaves, lower side, inset: detail of midrib, note the long soft hairs producing A whitish appearance B young branch, petiole and base of leaf, upper side, note the absence of hairs (fallen off) C flower, top view D flower, side view showing sepals and bracts E young fruit, top view. A Couvreur 1229 B-D Couvreur 1057. Photos Thomas Couvreur.

Figure 21. Uvariodendron fuscum var. giganteum (R. E. Fr.) Dagallier & Couvreur A leaf B flower bud, side view C flower bud, bracts removed, side view D detail of flower bud, two sepals, one outer and two inner petals removed E outer petal, outer view F inner petal, outer view G stamen H carpels, side view and detail of ovules I longitudinal section of receptacle J floral diagram K fruit, longitudinal sections of monocarps. A-K from Halle 3156 (as Ud. giganteum). Drawings by Helene Lamourdedieu, modified from Le Thomas (1969; pl. 50, p. 279), Publications Scientifiques du Museum national d'Histoire naturelle, Paris.

Figure 23. Distribution map of Uvariodendron fuscum. Shades of grey represent elevation, from white (sea level) to darker grey (higher elevation). The inset shows the extent of the map over Africa.