Monanthotaxis enghiana (Diels) P.H.Hoekstra, Taxon 66: 14, 2017

Couvreur, Thomas L. P., Dagallier, Leo-Paul M. J., Crozier, Francoise, Ghogue, Jean-Paul, Hoekstra, Paul H., Kamdem, Narcisse G., Johnson, David M., Murray, Nancy A. & Sonke, Bonaventure, 2022, Flora of Cameroon - Annonaceae Vol 45, PhytoKeys 207, pp. 1-532 : 192-195

Monanthotaxis enghiana (Diels) P.H.Hoekstra, Taxon 66: 14, 2017

Figs 53 , 54 ; Map 7D

≡ Popowia enghiana Diels, Wiss. Ergebn. Deut. Zentr.-Afr. Exped. (1907-1908), Bot. 2: 213, 1911; Friesodielsia enghiana (Diels) Verdc. in Le Thomas Fl. Gabon No. 16: 240, 1969.

= Oxymitra grandiflora Boutique, Bull. Jard. Bot. Etat Brux. 21: 116, 1951; Richella grandiflora (Boutique) R.E.Fr., in Engler & Prantl Nat. Pflanzenfam., ed. 2, 17a (2): 139, 1959; Fiesodielsia grandiflora (Boutique) Steenis, Blumea 12: 359, 1964. Type. Democratic Republic of the Congo. Orientale, Yalibutu, 45 km NW of Yangambi, Germain R.G.A. 883, 22 Jan 1948: lectotype, chosen by Hoekstra et al. (2021), p. 150: BR n.v.; isolectotypes: K [K000913652, K000913653]; MO n.v.

= Unona obanensis Baker f., Cat. Pl. Oban 4, 1913; Oxymitra obanensis (Baker f.) Sprague & Hutch., Bull. Misc. Inform. Kew 6: 156, 1916; Richella obanensis (Baker f.) R.E.Fr., in Engler & Prantl Nat. Pflanzenfam., ed. 2, 17 a (2): 139, 1959; Friesodielsia obanensis (Baker f.) Steenis, Blumea 12 (2): 359, 1964. Type. Nigeria. Cross River State, Oban, Talbot P.A. 1246, 1911: holotype: BM [BM000547069].

= Popowia mangenotii Sillans, Bull. Mus. Natl. Hist. Nat. sér. 2, 24: 578, 1953. Type. Central African Republic: Lobaye, Station de Boukoko, Boukokok, Tisserant C. ( Équipe) 1285, 14 Dec 1948: lectotype, chosen by Hoekstra et al. (2021), p. 150: P [P00363339]; isolectotypes: BR n.v.; K[K000913654]; P[P00363338].

= Popowia mangenotii f. concolor Sillans, Bull. Mus. Natl. Hist. Nat. sér. 2, 24: 580, 1953. Type. Central African Republic, Lobaye, Station de Boukoko, Boukokok, 5 Apr 1951. C. Tisserant ( Équipe) 2062: lectotype, chosen by Hoekstra et al. (2021), p. 150: P[P00363336]; isolectotypes: BM [BM000547068]; BR n.v., P[P003633385, P01985781].

Type.

Type. Democratic Republic of the Congo. Nord Kivu; Fort Beni à Semliki, Mildbraed G.W.J. 2213, 1907-1908: holotype: B[B100153056] .

Description.

Liana, up to 15 m tall or up to canopy, d.b.h. to 6 cm. Indumentum of simple hairs; old leafless branches glabrescent, young foliate branches densely pubescent with dense erect dark-brown hairs 0.9-1.4 mm long. Leaves: petiole 3-4 mm long, 1-2 mm in diameter, densely pubescent, slightly grooved, blade inserted on top of the petiole; blade 10.8-35 cm long, 3.3-7.5 cm wide, narrowly oblong to narrowly oblanceolate, apex acuminate to acute, acumen up to 5 cm long, base rounded to subcordate, subcoriaceous to membranous, below whitish blue, densely pubescent to pubescent with erect brown hairs when young, pubescent to glabrous when old, above pubescent when young, sparsely pubescent to glabrous when old, discolorous, whitish below; midrib impressed, above densely pubescent when young and old, below sparsely pubescent when young, glabrous when old; secondary veins 11 to 20 pairs, glabrous above; tertiary venation percurrent. Individuals bisexual; inflorescences ramiflorous on young foliate branches, extra axillary. Flowers with 9 perianth parts in 3 whorls, (1)2 to 5 per inflorescence; pedicel 18-22 mm long, 1-2 mm in diameter, densely pubescent; in fruit 18-22 mm long, 1-2 mm in diameter; basal bract ca. 2 mm long, 2-3 mm wide; upper bract 3-5 mm long, ca. 4 mm wide; sepals 3, valvate, basally fused, 3-5 mm long, 5-8 mm wide, ovate, apex rounded, base truncate, densely pubescent outside, glabrous inside, margins flat; petals free, outer petals longer than inner, inner petals entirely covered in bud; outer petals 3, 12-22 mm long, 7-14 mm wide, elliptic to ovate, apex obtuse, base truncate, brown-violet, margins flat, densely pubescent outside, pubescent with a glabrous base inside; inner petals 3, valvate, 9-14 mm long, 8-10 mm wide, ovate to rhombic, apex acute, base truncate, brown-violet, margins flat, glabrous but pubescent towards base outside, glabrous but pubescent towards the base inside; stamens 90 to 110, in 3 to 4 rows, ca. 1 mm long, cuneate; connective truncate, glabrous; staminodes absent; carpels free, 40 to 60, ovary ca. 3 mm long, stigma elongate, glabrous. Monocarps stipitate, stipes 2-5 mm long, 2 mm in diameter; monocarps 5 to 15, 14-18 mm long, 34 mm in diameter, moniliform, ellipsoid, apex rounded to apiculate, densely pubescent, smooth, constricted around seeds when more than 1, glaucous green when ripe; seeds 1 to 2(3) per monocarp, 11-12 mm long, 7-11 mm in diameter, ellipsoid; aril absent.

Distribution.

A widespread west and central African species, from Guinea to Ivory Coast, and from Cameroon to the Republic of the Congo, the Democratic Republic of the Congo, Central African Republic and Uganda; in Cameroon recorded from Adamaoua, Central, East, Littoral, South, South-West regions.

Habitat.

A very common and widespread species; in primary and young or old secondary rain forests, or semi-deciduous forests, submontane forests, gallery forests and swamp forests. Altitude 0-1200 m a.s.l.

Local and common names known in Cameroon.

Mavembegne ( Pygmée name, language not specified).

Preliminary IUCN conservation status.

Least Concern (LC) ( Hoekstra et al. 2021).

Uses in Cameroon.

None reported.

Notes.

Monanthotaxis enghiana is usually distinguished by the narrowly oblong to oblanceolate leaves that are whitish-blue below, and the long dense dark-brown erect hairs on the young foliate branches, petioles and lower side of leaf blades. Some specimens have oblong leaves and can be confused with M. hirsuta when sterile. However, this latter species has much larger flowers (the petals being more than twice as long) and its thecae cover more than half the stamen length, while in M. enghiana the thecae are very short covering less than half the stamen length. Monanthotaxis enghiana is also morphologically close to M. dielsiana and M. glaucifolia , but clearly differs in the pubescence type.

This is one of the most common species of Annonaceae across the forest region of Cameroon. It is generally encountered as a sapling on the forest floor. As for most lianas, it resembles a scrambling shrub when juvenile, sometimes forming large clumps.

Selected specimens examined.

Adamaoua Region: Mbakaou , 6.00°N, 12.88°E, 12 January 2017, Kamdem N. 465 (YA) . Central Region: Mefou proposed national park Near Mefou town, 3.62°N, 11.58°E, 08 March 2004, Cheek M. 11499 (K,YA); Ottotomo Forest reserve 7 km north-west from Ngoumou 30 km south west from Yaoundé, 3.65°N, 11.28°E, 24 February 2016, Couvreur T.L.P. 986 (WAG,YA); Ngoro, 5.07°N, 11.22°E, 29 April 2017, Kamdem N. 499 (YA) . East Region: 18 km NW of Doumé along road to Nguélémendouka, 4.23°N, 13.45°E, 24 November 1961, Breteler F.J. 2137 (BR,P,WAG,YA); 75 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 , 3.15°N, 14.73°E, 05 March 2019, Couvreur T.L.P. 1201 (MPU,WAG,YA); Palisco forest consession 15 km along main road into consession, 3.48°N, 13.59°E, 27 March 2015, Couvreur T.L.P. 754 (WAG,YA); Deng Deng, 5.20°N, 13.13°E, 27 July 2014, Kamdem N. 167 (YA); Route Bertoua-Deng Deng à 6 km au Sud de Mambaya , 4.91°N, 13.76°E, 26 January 1961, Letouzey R. 3248 (P,YA); A 15 km au S de Djouo (20 km E de Somalomo sur le Dja), 3.32°N, 12.93°E, 23 February 1962, Letouzey R. 4359 (P,YA); A 20 km au S de Mvoy I (45 km à l'Est de Yokadouma ), 3.31°N, 15.51°E, 16 May 1963, Letouzey R. 5071 (P,YA) . Littoral Region: Mapubi 30 km before Edea on Yaoundé-Edea road On forestry road 5 km direction to Sanaga river , 3.84°N, 10.38°E, 28 February 2018, Couvreur T.L.P. 1176 (MPU,WAG,YA); Ebo Wildlife Reserve Djuma permanent camp On Djashaka trail, 4.35°N, 10.24°E, 13 February 2014, Couvreur T.L.P. 618 (WAG,YA); Mambe Massif above Boga village 100 km along road from Yaoundé to Ed 3.91°N, 10.77°E, 19 June 2014, Couvreur T.L.P. 653 (WAG,YA); Ebo forest reserve ca 2500 m on Dicam trail from Bekob camp, 4.34°N, 10.40°E, 11 March 2007, Wieringa J.J. 5898 (WAG) . South Region: 20 km from Kribi 2 km N of Lolodorf road, 3.01°N, 10.05°E, 12 December 1969, Bos J.J. 5818 (WAG); 24 km from Kribi ca 3 km N of Lolodorf road, 3.03°N, 10.08°E, 31 March 1970, Bos J.J. 6653 (BR,K,LD,LM,MO,P,WAG,YA); 20 km east from Lélé village, 2.27°N, 13.33°E, 07 September 2013, Couvreur T.L.P. 466 (WAG,YA); Campo Ma'an National Park 11 km on trail from Ebinanemeyong village on road 7 km from Nyabessan to Campo town , 2.47°N, 10.33°E, 11 February 2015, Couvreur T.L.P. 669 (WAG,YA); Campo Ma'an National Park 11 km on trail from Ebinanemeyong village on road 7 km from Nyabessan to Campo town , 2.47°N, 10.33°E, 12 February 2015, Couvreur T.L.P. 691 (WAG,YA); Ebom, 3.1°N, 10.71°E, 27 February 1997, Parren M.P.E. 23 (KRIBI,WAG); Bipindi, 3.08°N, 10.42°E, 01 May 1913, Zenker G.A. 357 (M,P,U,WAG) . South-West Region: Kupe village, 4.76°N, 9.694°E, 21 May 1996, Cable S. 2523 (K); Gully by Daniel Ajang’s saprophyte site, 4.78°N, 9.716°E, 07 July 1996, Cable S. 3683 (K,YA); Bayang Mbo Wildlife Sanctuary after Mbu river, 5.35°N, 9.502°E, 25 March 2016, Couvreur T.L.P. 1003 (WAG,YA); Mount Cameroon National Park Bakinguili trail above Bakinguili village , 4.09°N, 9.057°E, 02 April 2016, Couvreur T.L.P. 1037 (WAG,YA); on forest trail north of Ngomboku village , 4.91°N, 9.730°E, 06 April 2016, Couvreur T.L.P. 1065 (WAG,YA); Etome, 4.05°N, 9.116°E, 31 January 1997, Nning J. 212 (K,MO,YA); Bakingili, 4.06°N, 9.033°E, 15 February 1997, Nning J. 259 (K,YA); Mahole, 4.81°N, 9.615°E, 29 November 1999, Onana J.M. 947 (K,MO,WAG,YA) .

Figures

Map 7. A Monanthotaxis diclina B Monanthotaxis dielsiana C Monanthotaxis elegans D Monanthotaxis enghiana E Monanthotaxis ferruginea F Monanthotaxis filamentosa G Monanthotaxis foliosa H Monanthotaxis glaucifolia I Monanthotaxis gracilis. White borders represent region limits in Cameroon; green patches represent protected areas (see methods and Suppl. material 1: Fig. S 1).

Figure 53. Monanthotaxis diclina A detail of base of leaf blades, upper view B leaf, upper view C leaf, lower view D detail of female flower receptacle, note the two small inner petals (yellow) at base of carpels, the larger petals are the outer ones (one removed) E cauliflorous inflorescences with female flowers and fruits F fruits, moniliform in shape. Monanthotaxis enghiana G leaves, top view H leaves, upper and lower views, note whitish lower side of leaves I detail of base of leaf base with erect pubescence, upper view J detail of base of leaf base with erect pubescence, lower view A-F Couvreur 537, Gabon G-J Couvreur 1121, Gabon. Photos Thomas L. P. Couvreur.

Figure 54. Monanthotaxis enghiana A fruiting branch B detail leaf, lower side C inflorescence D outer petal, inner side E inner petal, sinner side F flower with petals removed G stamen front and side view H carpel and longitudinal section of carpel I longitudinal section of carpel J transverse section of carpel A, I, J from Sillans 1701 A-H from Tisserant 1941. Drawings by Helene Lamourdedieu, Publications Scientifiques du Museum national d'Histoire naturelle, Paris; modified from Le Thomas (1969 b, pl. 43, p. 241).