Uvariastrum zenkeri Engl. & Diels, Bot. Jahrb. Syst. 39: 473. 1907.

Couvreur, Thomas L. P., 2014, Revision of the African genus Uvariastrum (Annonaceae), PhytoKeys 33, pp. 1-40 : 24-29

5. Uvariastrum zenkeri Engl. & Diels, Bot. Jahrb. Syst. 39: 473. 1907. Figure 12

Uvariastrum zenkeri Engl. & Diels var. nigritanum Baker f., Cat. Talbot’s Plants 3. 1913. Type. Nigeria. Cross River State: Oban district, recd. at Paris 21 Feb 1912, P.A. Talbot 1341 (lectotype, here designated: K!; isotypes: FHO! [accession number 15560, barcode 3586], P! [P01983332]).

Uvariastrum pynaertii De Wild., Ann. Mus. Congo Belge, Bot. sér. 5, 3[1]: 74. 1909. Type. Democratic Republic of Congo. Equateur: Eala, Mar 1907 L.A. Pynaert 1234 (lectotype designated by Le Thomas (1969) pp. 292, sheet designated here: BR! [BR0000008824288]; isolectotypes: BR! [BR0000008824295, BR0000008824301], S!) syn. nov.

Type.

Cameroon. South Province: Bipindi, 1904, G.A. Zenker 2935 (lectotype, here designated: B! [B100153114]; isolectotypes: B! [B100190283], BM!, [BM000554069], BR!, 2 sheets COI!, GOET! [GOET005731], G! 2-sheets [G00011742, G00011744], HBG!, K! [K000198808], L! [L0191076], M! [M0089220], MA! [MA215566-3], P! [P00315826], S!, WAG! [WAG0057973], WU! [WU0025789], Z! 2-sheets [Z000034578, Z000034577]).

Description.

Tree or shrub to 20 m high, d.b.h. up to 30 cm; old branches spreading, glabrous, bark brown-grey; young branches glabrous to very sparsely pubescent, hairs ca. 0,1 mm long, appressed, light brown soon disappearing; leaf buds elongated, pubescent, hairs ca. 0.2 mm long, appressed, light brown. Petioles 2-3 mm long, 1.5-2 mm in diameter; glabrous, or rarely very sparsely pubescent, hairs tiny, light brown, soon falling off; leaf lamina inserted on top, not grooved adaxially. Leaf lamina (12-)15-22 cm long, 3-5 cm wide, length:width ratio 2-4.7, narrowly elliptic to elliptic or narrowly obovate to obovate, coriaceous, glabrous adaxially, sparsely pubescent, hairs tiny, light brown, becoming quickly glabrous abaxially; lamina dark green adaxially; slightly lighter green abaxially; base rounded to cuneate, apex acuminate, acumen 1-2 cm long; midrib glabrous on both sides; secondary veins 11-17, curving upwards, anastomizing near margins, glabrous, slightly raised adaxially; clearly visible abaxially. Raphidia 1-2 on young and old braches, cauliflorous with numerous flowers. Flowering pedicels 1.3-3 cm long, 1-2 mm wide, glabrous to very sparsely pubescent, hairs ca. 0.1 mm long, appressed, light brown, drying black or brown, brown to dark green in fresh material. Bracts up to 3, basal, up to 5 mm long, 3 mm wide, length:width ratio 1.6, ovate, sparsely pubescent outside, glabrous inside. Flower buds pyramidal, up to 2.5 cm long, up to 1.5 cm in diameter, margins weakly to strongly folded. Sepals 1.5-2.5 cm long, 0.8-1.5 cm wide, length:width ratio 1.2-2, ovate to broadly ovate, base truncate, apex acute, margins clearly recurved, glabrous or sparsely pubescent outside, hairs 0.1-0.2 mm long, appressed, light brown, tomentose light brown inside along the margins, glabrous towards the center; sepals conspicuously black outside, light brown inside but black at the centre on dry material; same color as flowering pedicels on fresh material, spreading horizontally at anthesis. Outer petals 2-3.5 cm long, 0.8-1.5 cm wide, length:width ratio 2-3.5, ovate to narrowly ovate or elliptic to narrowly elliptic, base truncate, apex acute, densely pubescent outside more so along the main vein, hairs ca. 0.1-0.2 mm long, appressed, light brown shiny, pubescent along the margins to glabrous at the center inside, hairs ca. 0.1 mm long, appressed, light brown; petals light brown outside, light brown to black inside in herbarium material, white turning bright yellow to orange in fresh material, light grey when old; spreading horizontally at anthesis. Inner petals 1.5-2.5 cm long, 0.7-1 cm wide, length:width ratio 1.5-3.5, ovate to narrowly ovate, base truncate, apex acute, pubescence same as outer petals, color same as outer petals, connivent to appressed by the margins, the top open. Receptacle pyramidal with a flat apex. Stamens 2-4 mm long, connective discoid, pubescent, ca. 0.2 mm in diameter, red in fresh material. Carpels (1-3-)5-15, 3-5 mm long, ca. 1 mm in diameter, stigma capitate, ca. 0.7 mm in diameter, glabrous or sometimes very sparsely pubescent, drying black; ovules numerous. Fruiting pedicels 1.5-3 cm long, 2-5 mm in diameter, woody, glabrous. Monocarps 2-5, up to 8 cm long, up to 2.5 cm in diameter, oblong to narrowly oblong, straight to slightly bending, apex acute, longitudinally ribbed, main ribs 5-6, sometimes with smaller latitudinal ribs, glabrous to sparsely pubescent, hairs ca. 0.1 mm long, appressed, light brown; stipe 2-5 mm long, ca. 5 mm in diameter; monocarps. Seeds 20-27 per monocarp, 1.5-2 cm long, 1-1.5 cm wide, ellipsoid flat, ca. 5 mm in depth, testa light brown in herbarium material, raphe very slightly raised, hilum 3-4 mm long, 2-3 mm wide, narrowly elliptic.

Distribution.

This species has a strict Central African distribution occurring from extreme east Nigeria and South East Cameron till Democratic Republic of Congo; 0-600 m. Figure 13 .

Habitat and ecology.

Occurring in primary or secondary lowland rain forest, on tierra firme with well drained soils, but also on marshy or sandy soils; 0-400 m.

Phenology.

Flowering and fruiting all year round across its distribution range.

Preliminary IUCN conservation status.

LC. This species has a wide distribution across the Congo basin. It occurs in numerous national parks (Korup National Park (Cameroon); Loango National Park (Gabon) and other protected areas, and it is often collected. The least concern category is appropriate. Onana et al. (2005) gave the Near Threatened (NT) status to Uvariastrum zenkeri , but this was before Uvariastrum pynaertii was sunken into synonymy and thus based on a smaller distribution.

Vernacular names.

Democratic Republic of Congo: Bolésé na mai (Kunau, Coûteaux, G. 337); Etunduluku (Corbisier-Baland, A. 942) Moukassa (Corbisier-Baland, A. 1386); Bokako (Corbisier-Baland, A. 2051); Mukobakoba mufike (Tshiluba; Dechamps, R. 80); Inaolo a Loopa (Turumbu; Germain, R.G.A. 4562)

Uses.

None recorded.

Notes.

This species is easily distinguished by the sepals that dry black and the large leaves with the leaf lamina inserted on top of the petiole. The black color of the dried sepals is related to the glabrous or sparsely pubescent outer side of the sepals, whereas it is pubescent in the other species.

Carpel number in this species appears very variable. The higher number of carpels compared to the other species ( Uvariastrum zenkeri and Uvariastrum pierreanum ) was one of the reasons why De Wildeman (1909) described the species Uvariastrum pynaertii . I have counted the carpels for several specimens from DRC to Nigeria and there is a clear continuous variation from 1 to 15. The specimen with a single carpel is intriguing and has been described as a variety Uvariastrum zenkei var. nigritanum (Talbot 1314). However, all other aspects of its morphology lead me to not accept it as distinct even at the rank of variety. What I can see is an increase in carpel number from Nigeria/Cameroon (3-5-10) to DRC (9-15), but this variation has yet to be properly explored. For these reasons I will keep this variation under a single species name.

The lectotype of Uvariastrum zenkeri designated here followed the unpublished flora of Cameroon ( Annonaceae ) by Le Thomas (1969) that is archived at the Museum National d’Histoire Naturelle in Paris, kindly made available by Dr. Thierry Deroin. Le Thomas selected Zenker 2935 as the lectotype over Zenker 2438, the other syntype cited in the protologue. Because the former is more widely distributed I agree with her choice and select the B sheet designated here.

In the "Catalogue of the plants collected by Mr. and Mrs. P.A. Talbot" ( Rendle et al. 1913) Baker indicates two collection numbers for var. nigritanum (pp 120): Talbot 3 and 1341. The protologue clearly indicates that Talbot 1341 is the type. Of the 4 specimens I have located, the BM sheet has no indication of either the name or the collection number and with a 1911 date (indicated via a small stamp). The other sheets (FHO, K, P) all have the name, the collection number and the date (1912, see below). This leads me to suspect that the BM sheet is in fact Talbot 3 and thus isn’t a type specimen. I here select the K! sheet as the holotype as this would have been seen by Baker (based in BM or K) and I do not consider the BM sheet as being a type specimen.

Selected specimens examined.

Cameroon. East Province: department Haut-Nyong. Dja Reserve. Bouamir Reseach area. 90km Southeast of Akonolinga. Study plot 12, Ind: 12W12, 4 Nov 1994, Fogiel, M.K. 1039 (MO, P). South Province: 40 km N. of Kribi, 5 km E. of Edea road, forest track Fifinda-Bella, 6 Feb 1970, Bos, J.J. 6266 (BR, C, K, LD, LISC, LMA, MO, P, PRE, UPS, WAG, YA); Bipindi, Jan 1914, Zenker, G.A. 481 (B, BR, C, F, G, GH, M, NY, P, S, U, US, WAG, Z); Kamerun. Bipinde, 1902, Zenker, G.A. 2438 (B, COI, G, K, L, MO, P, S, WAG, Z); Bipinde, 1912, Zenker, G.A. 4473 (B, COI, FHO, G, HBG, L, M, P, S); 1907, Zenker, G.A. 3409 (COI, G, HBG, L, M, MO, P, S, US, WRSL, Z); Bipinde, 1907, Zenker, G.A. 3289 (B, L, S, WU, Z); entre 15 et 25 km au SW de Zingui. Soit à 45km au SSE de Kribi, 22 Mar 1968, Letouzey, R. 9121 (P); Bipinde, Mar 1907, Zenker, G.A. s.n. (P); Bipindi, May 1904, Zenker, G.A. s.n. (F); Bipinde, 1906, Zenker, G.A. 3248 (K). South-West Province: Korup National Park, P transect, plot 22U, 4 Feb 2000, Burgt, X.M. van der 590 (G, SCA, WAG); Korup National Park, P transect, near P plot, subplot 19Y, 19 Mar 2004, Burgt, X.M. van der 674 (BR, G, K, MO, P, SCA, WAG, YA); Korup Forest Dynamics Plot, Korup National Park, 12 Jan 1998, Kenfack, D. 1008 (MO, WAG); Korup national park, forest along footpath from Ndian River at PAMOL fields 69 and transect P, 24 Jan 1985, Thomas, D.W. 4334 (K, MO, P, US); Ideano, West bank of the Onge River, seasonally exposed cobble in river bed, large rocks (shaded and exposed) riparian forest with Oubanguita alata, 7 Nov 1993, Thomas, D.W. 9772 (K, MO, P, SCA, WAG, YA); Mabeta/Moliwe, 2 Apr 1992, Bongyu, J. 42 (K,P); Korup reserve, transect P, 12 Jan 1979, Thomas, D.W. 604 (K).

Democratic Republic of Congo. Bandundu: Bankaie, 29 Jun 1953, Gilbert, G.C.C. 14329 (BR); 5 Jul 1953, Gilbert, G.C.C. 14552 (BR); Ipeke, 29 Jul 1953, Gilbert, G.C.C. 14560 (BR); Bankaie, 10 Jun 1953, Gilbert, G.C.C. 14045 (BR, WAG); Bankai, 7 Jul 1953, Gilbert, G.C.C. 14362 (BR,W AG). Equateur: Equateur, Bikoro, raute Weti-Iboko, Apr 1959, Evrard, C.M. 6190 (L); entre Bokatola et Bikoro, 7 Sep 1930, Lebrun, J.-.P.A. 1406 (A, BR, P 2 sheets); Eala, Oct 1930, Staner, P.J. 1274 (K, P); Coquilhatville, 1930, Lebrun, J.-.P.A. 1199 (A, B, G, K, NY, P); Eala, 27 Sep 1933, Corbisier-Baland, A. 2051 (BR, MO, NY, P, WAG); 1936, Leemans, J. 346 (BR, P); environs d’Eala, 11 May 1905, Laurent, M.D.J. 664 (S, US, Z); Bongoy, 6 Jan 1958, Evrard, C.M. 3235 (F); Watsi, 9 Feb 1959, Evrard, C.M. 5635 (Z); Eala, 9 Mar 1931, Corbisier-Baland, A. 942 (BR); 14 Apr 1932, Corbisier-Baland, A. 1386 (BR); 28 Sep 1937, Coûteaux, G. 337 (BR); Coquitaville, 2 Jan 1896, Dewèvre, A.P. 591 (BR); rivière Salonga, rive gauche, 3 km en amont de la Yenge. Monkoto Parc National, 5 Aug 1958, Evrard, C.M. 4500 (BR); piste Nkinki-Pomandjoku. Monkoto Parc National, 12 Aug 1858, Evrard, C.M. 4616 (BR); piste Eungu-Imbonga, 11 Apr 1959, Evrard, C.M. 6073 (BR); route ITIPO-IBOKO, 15 Apr 1959, Evrard, C.M. 6150 (BR); Eala, 1936, Leemans, J. 443 (BR); Bandaka, N’Koli, 25 Jun 1907, Vanderwegen, C. s.n. (BR); Eala, Dec 1906, Pynaert, L.A. 725 (BR); Jun 1907, Pynaert, L.A. 1560 (BR); 22 Jan 1907, Pynaert, L.A. 982 (BR); 30 Apr 1908, Seret, F. 806 (BR). Kasai-Occidental: Kakenge, 575m, 20 Nov 1958, Dechamps, R. 80 (BR, WAG). Kasai-Oriental: entre Lodga et Kole, Sep 1932, Lebrun, J.-.P.A. 6266 (K, P). Orientale: entre Yafela et Yandjali, Dec 1948, Germain, R.G.A. 4562 (BR).

Gabon. Estuaire: Ndombo oil-concession area of CONOCO; ca 3 km SW of No Ayong, 28 Feb 1991, Reitsma, J.M. 3711 (LBV, WAG); forêt classée de la Mondah: site combat 2, 16 Oct 2009, Bissiengou, P. 288 (LBV, WAG); Agonenzorck, sur le Haut-Komo, 7 Oct 1912, Chevalier, A.J.B. 26973 (P). Moyen-Ogooué: Ezanga. Layon D ouest, 1991, Wilks, C.M. 2465 (LBV, WAG). Nyanga: Gamba area, 32 km on road to Bouda (NE of Gamba), 28 Dec 1995, Bergen, M.A. van 200 (LBV, WAG); Inventory; chantier CEB, c. 50 km SW of Doussala; primary rain-forest, 17 Oct 1985, Reitsma, J.M. 1640 (LBV, WAG); Tchibanga area, Mindounga, Oct 1910, Le Testu, G.M.P.C. 1638 (P); Mayumba, 30 Jan 1904, Chevalier, A.J.B. 11303 (P); région du Mayumbe, à l’ouest du village de Biboura situé sur la route menant à la république du Congo, 22 Mar 2012, Dauby, G.V. 2553 (BRLU). Ogooué-Ivindo: M’passa, 7 Apr 1978, Florence, J. 860 (P); Makokou. Station d’IPASSA, 10 km S of Makoukou, 29 Jun 1978, Florence, J. 1472 (P); Makokou. Transect 8, 9 Jul 1981, Gentry, A.H. 33253 (MO); Makokou. Transect 17, no date, Gentry, A.H. 33443 (MO); Makokou, bord de l’Ivindo, 16 Mar 1961, Hallé, N. 1491 (P). Ogooué-Lolo: Chantier forestier de vouboué à 10 Km du Campement à l’ouest dans les abattages, 30 Aug 1983, Sita, P. 5195 (LBV); region de Koulamoutou, Koulamoutou, Mar 1930, Le Testu, G.M.P.C. 7996 B (P); région de Lastoursville, Koulamotou, 21 Oct 1930, Le Testu, G.M.P.C. 8462 (P); region de Lastoursville, Malendé, 24 Jan 1930, Le Testu, G.M.P.C. 8473 (P, WAG); c.40 km ENE of Lastoursville, 20 km on forestry road from Bambidie heading N, 25 Jan 2008, Wieringa, J.J. 6157 (LBV, WAG). Ogooué-Maritime: Gamba-E, road from Gamba airport to the north, new laterite road direction ‘plaines’ (only for services), 11 Nov 1990, Nek, F.I. van 262 (LBV, WAG); Vera plains, transect II, forest plot, 13 Mar 1996, Bergen, M.A. van 335 (WAG); Doudou Mountains National Parc, c. 5 km S of Camp Peny (CBG), 14 Nov 2005, Sosef, M.S.M. 2277 (BR, LBV, MO, WAG); Doudou Mountains National Parc, c. 5 km S of Camp Peny (CBG), 14 Nov 2005, Sosef, M.S.M. 2282 (BR, E, HUJ, K, LBV, MO, WAG); Loango National Park, Nick’s camp, by Louri lagoon, c. 12 km south of Iguela, 2 May 2005, Harris, D.J. 8300 (E, LBV, WAG); Loango National Park, Nick’s camp, by Louri lagoon, c. 12 km south of Iguela, 3 May 2005, Harris, D.J. 8337 (E, IG, LBV, WAG); Parc National de Loango, near Tassi, 22m, 7 Nov 2011, Maas, P.J.M. 10143 (LBV, MO, UC, WAG). Woleu-Ntem: forestry concession Bordamur, c. 50 km NE of Mitzic, 11 Feb 2003, Sosef, M.S.M. 1992 (LBV, WAG).

Nigeria. Cross River State: Oban district, 1911, Talbot, P.A. 1341 (FHO, P); Oban, 1912, Talbot, P.A. s.n. (K).

Republic of Congo. Cuvette: Park National d’Odzala, Foret d’Andzoyi, entre Mboko et Mbomo, Jan 1994, Dowsett-Lemaire, F. 1736 (BR). Kouilou: Koubotchi (Kayis), 1 Sep 1990, Moutsamboté, J.M. 80 (BR). Pool: Région de Kimba, à 21 km de Kimba, 15 Dec 1971, Sita, P. 3248 (P).

Figures

Figure 12. Uvariastrum zenkeri. A leaf B, C cauliflorous flowers D detail of flower with three petals removed E detail of receptacle F sepals G carpels H stamens I detail of monocarp. Drawing Helene Lamourdedieux, EPHE in MNHN-Palynotheque (Paris).

Figure 13. Distribution of Uvariastrum zenkeri.