Artabotrys thomsonii Oliv., Fl. Trop. Afr. 1: 28, 1868

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 : 75-78

Artabotrys thomsonii Oliv., Fl. Trop. Afr. 1: 28, 1868

Figs 17 , 18 ; Map 2I

Type.

Nigeria. Cross River State; Old Calabar, Thomson W.C 25, Feb 1863: holotype: K[K000198871] .

Description.

Liana, 30 m tall, d.b.h. 10-20 cm. Indumentum of simple hairs; old leafless branches sparsely pubescent to glabrous, young foliate branches sparsely pubescent. Leaves: petiole 1-10 mm long, ca. 2 mm in diameter, pubescent to glabrous, slightly grooved, blade inserted on top of the petiole; blade 7-20 cm long, 5-10 cm wide, elliptic to oblong, apex acute to abruptly acuminate, acumen 0.5-1 cm long, base rounded to obtuse, coriaceous, below sparsely pubescent to glabrous when young, sparsely pubescent to glabrous when old, above glabrous when young and old, concolorous; midrib impressed, above densely pubescent to pubescent when young and old, below sparsely pubescent to glabrous when young and old; secondary veins 7 to 14 pairs, glabrous above; tertiary venation intermediate. Individuals bisexual; inflorescences ramiflorous on old leafless branches, leaf opposed. Flowers with 9 perianth parts in 3 whorls, 30 to 90 per inflorescence, hook-shaped peduncle 20-35 mm long; pedicel 10-20 mm long, ca. 1 mm in diameter, pubescent; in fruit 10-25 mm long, ca. 2 mm in diameter, pubescent; bracts several, basal with one towards the lower half of pedicel, soon falling, basal bracts ca. 1 mm long, ca. 1 mm wide; upper bract ca. 2 mm long, ca. 2 mm wide; sepals 3, valvate, free, 2-3 mm long, 2-3 mm wide, triangular, apex acute, base truncate, pubescent outside, glabrous inside, margins flat; petals free, sub equal; outer petals 3, 10-20 mm long, 2-3 mm wide, elliptic to narrowly elliptic, apex rounded to obtuse, base broad and concave, margins flat, not folded inwards, pubescent outside, pubescent with a glabrous base inside; inner petals 3, valvate, 12-16 mm long, 2-3 mm wide, narrowly elliptic, apex acute, base broad and concave, margins flat, not folded inwards, pubescent outside, pubescent inside; stamens 30 to 35, in 2 to 3 rows, ca. 1 mm long, cuneiform; connective discoid, glabrous; staminodes absent; carpels free, 4 to 10, ovary ca. 1 mm long, stigma coiled, sparsely pubescent. Monocarps stipitate, stipes 10-25 mm long, 2-3 mm in diameter; monocarps 1 to 7, 15-25 mm long, 12-15 mm in diameter, ellipsoid to obovoid, apex rounded, glabrous, smooth, not ribbed, green when ripe; seeds 1 (to 2) per monocarp, 10-15 mm long, 8-9 mm in diameter, ellipsoid; aril absent.

Distribution.

A central African species; from Nigeria to Angola (Cabinda) and in the Democratic Republic of the Congo; in Cameroon known from the Central, East, Littoral, South, South-West and West regions.

Habitat.

A common species, in lowland and premontane secondary or primary rain forests, along forests margins and in logging areas. Altitude 100-1000 m a.s.l.

Local and common names known in Cameroon.

None recorded.

IUCN conservation status.

Not evaluated.

Uses in Cameroon.

food: water drinken from stem; medicine: water/sap used for liver, genital stimulant/depressants, pregnancy, antiaborifacients.

Notes.

Artabotrys thomsonii is easily distinguished by the densely pubescent upper midrib which is not found in any other Cameroonian species of Artabotrys .

There seems to be confusion around the type specimen of the name Artabotrys thomsonii . In the protologue, Oliver (1868, p. 28) indicates " Thomson!, Old Calabar" as the type. In the Flore du Gabon, Le Thomas (1969b) indicates that the type is Thomson s.n., and notes that the sheet deposited in Kew is a mixed collection: pro parte with the fruits and associated leaves belonging to a different species (see below). This corresponds to specimen K000198872, labeled as Thomson 2310. However, this collection belongs to Mann 2310 (interestingly Le Thomas didn’t mention the number when it is clearly indicated) and not Thomson 2310 as indicated. The Kew specimen is confusing because it clearly says "collected by Rev W. C. Thomson" followed by the number 2310 with no mention of Mann. However, the duplicate in B [B 10 0154054] says "Old Calabar River, G. Mann 1863" followed by the mention "same as [hard to read, personal interpretation] Rev. W. Thomson". The specimen in P [P00363393] has an identical handwriting and text as the one in B, but also has the mention "from Rev. W. Thomson". However, the handwriting (same as in other true Mann collections) and high number (+2000) suggest this is a Mann collection and thus not the type (Thomson W.C. collections are below 150 from what we can see in K).

The collection Thomson 25 is without doubt a Thomson collection with a printed label indicating "Collected at Old Calabar, by the Rev. W.C. Thomson" followed by "Presented by Professor Balfour, Dec; 1963". Indeed, some specimens of Thomson were forwarded by Balfour to Kew ( Oliver 1865, p. 156).

For what it is worth, the fruit and leaves on Mann 2310 (K [K000198872] and P [P00363393]) appear to belong to Neostenanthera myristicifolia (Oliv.) Exell also present in Nigeria.

Specimens examined.

Central Region: Yaoundé, 3.87°N, 11.52°E, 1896, Zenker G.A. 697 (P). East Region : Near Dimako 28 km SW of Bertoua, 4.38°N, 13.57°E, 01 August 1961, Breteler F.J. 1725 (BR,K,P,U,WAG,YA); Bertoua 6 km along road to Batouri and Betaré-Oya, 4.58°N, 13.68°E, 30 August 1961, Breteler F.J. 1797 (U,WAG,YA); 67 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 , 3.08°N, 14.67°E, 08 March 2019, Couvreur T.L.P. 1230 (MPU,WAG,YA); Palisco forest consession 15 km along main road into consession, 3.52°N, 13.54°E, 27 March 2015, Couvreur T.L.P. 751 (WAG,YA); 20 km environ à l’ENE de Mikel village situé à 85 km au N de Moloundou sur la route de Yokadouma 2.81°N, 15.24°E, 23 February 1971, Letouzey R. 10413 (K,P,YA); Ndongo (Dja-Molundou), 2.58°N, 15.29°E, 18 March 1973, Letouzey R. 12240 (K,P,YA); Djouo (Somalomo), 3.32°N, 12.93°E, 26 February 1962, Letouzey R. 4435 (K,P,YA); A 8 km au SSW de Koso (village situé à 60 km au SSW de Batouri), 3.93°N, 14.17°E, 29 July 1963, Letouzey R. 5533 (P,YA); Entre Badekok et Mpan (50 km ENE de Lomié), 3.22°N, 15.02°E, 05 August 1963, Letouzey R. 5548 (P,YA). Littoral Region : 8 km W of Massok, 4.13°N, 10.47°E, 27 March 1965, Leeuwenberg A.J.M. 5201 (B,BR,C,GC,K,MO,P,UC,WAG,YA). South Region : Bitya near R Ja, 3.02°N, 12.37°E, 01 November 1922, Bates G.L. 1763 (P); Djoum North East Nkout Base of ridge, 2.55°N, 12.80°E, 05 December 2014, Cheek M. 17781 (K,WAG); Elephant Mont, 2.8°N, 10.01°E, 24 May 2001, van Andel T.R. 3459 (KRIBI,WAG,YA); Campo-Ma’an area 2.73°N, 9.873°E, 16 August 2001, van Andel T.R. 3872 (KRIBI,U,WAG); Nkuambe, 3.26°N, 10.46°E, 01 December 1914, Zenker G.A. 489 (P,WAG). South-West Region : Bayang Mbo Wildlife Sanctuary after Mbu river, 5.35°N, 9.497°E, 27 March 2016, Couvreur T.L.P. 1020 (WAG,YA); Ekombe, 4.48°N, 10.87°E, 16 January 1987, Etuge M. 485 (MO,P,WAG). West Region: Près Bandounga à 40 km au NW de Ndikinimeki, 4.98°N, 10.55°E, 12 February 1972, Letouzey R. 11200 (P,YA) .

Figures

Map 2. A Artabotrys aurantiacus B Artabotrys aurantiacus var. multiflorus C Artabotrys congolensis D Artabotrys dielsianus E Artabotrys insignis F Artabotrys insignis var. batesii G Artabotrys jacques-felicis H Artabotrys rufus I Artabotrys thomsonii. White borders represent region limits in Cameroon; green patches represent protected areas (see methods and Suppl. material 1: Fig. S 1).

Figure 17. Artabotrys thomsonii A flowering branch B outer petal, inner view C inner petal, inner view D flowering receptacle, petals removed E stamens, front and side views F carpel, side and detail of ovules G fruiting peduncle. Artabotrys rufus H flowering branch I flowering receptacle with one outer petal removed J outer petals, outer view and inner views K inner petals, inner and outer views L flowering receptacle, petals removed M stamen N carpel, side view and detail of ovule O fruiting peduncle A-G from Le Testu 9249 H-N from Hall 3193; 15 from Hall 3528. Drawings by Helene Lamourdedieu, Publications Scientifiques du Museum national d'Histoire naturelle, Paris; modified from Le Thomas (1969 b, pl. 23, p. 441 (A. rufus )).

Figure 18. Artabotrys thomsonii A branch B base of leaf blade, upper side, note densely pubescent midrib and glabrous blade C base of leaf blade, lower side A-C Couvreur 751, Mindourou, Cameroon. Photos Thomas L. P. Couvreur.