Monanthotaxis laurentii (De Wild.) Verdc.

Hoekstra, P. H., Wieringa, J. J., Maas, P. J. M. & Chatrou, L. W., 2021, Revision of the African species of Monanthotaxis (Annonaceae), Blumea 66 (2), pp. 107-221 : 171

42. Monanthotaxis laurentii (De Wild.) Verdc. — Fig. 18j–o ; Map 27

Monanthotaxis laurentii (De Wild.) Verdc.(1971b) 26. — Popowia laurentii De Wild.(1905b) 19. — Type: É. Laurent 92 (holo BR0000008805010 ), Democratic Republic of the Congo, Equateur, Bikoro, Lukolela, 13 Dec. 1903.

Unona congensis Engl.& Diels (1899) 296.— Popowia congensis (Engl.& Diels) Engl. & Diels (1901) 44. — Type: É. Laurent s.n. (holo BR0000008804686 ), Democratic Republic of the Congo, Equateur, Bomongo, Bangala, 20 Feb. 1896.

Scandent shrub or liana, to 20 m long; young branches reddish brown, sparsely covered with appressed to ascending, yellowish hairs 0.2–0.3 mm long, becoming glabrous; old branches reddish brown. Leaves: petiole 3–6.5 mm long, 0.7–1.3 mm diam, slightly grooved, indument slightly more dense than on branches; lamina oblong-elliptic to obovate or narrowly so, 4.7– 18.3 by 2.4–7.2 cm, 1.7–2.6 times longer than wide, chartaceous, not punctate, dull green above, glaucous below, above sparsely covered with appressed, white hairs 0.3–0.5 mm long, becoming glabrous, primary vein with longer persistent white-yellowish hairs 0.3–0.5 mm long, below sparsely covered with appressed, yellowish hairs 0.1–0.3 mm long, slightly more dense on veins, becoming glabrous, base rounded or slightly subcordate, glands hardly visible, apex acute to acuminate, acumen to 20 mm long, secondary veins 7–14 per side, slightly curving upwards, tertiary venation percurrent. Inflorescences extra-axillary, leaf-opposed or terminal, composed of solitary flowers or 2-flowered rhipidia; sympodial rachis absent or up to 5 mm long, densely covered with appressed, yellowish hairs; pedicels 5–9(–11) mm long, 0.5–0.8 mm diam, fruiting pedicels 15–23 mm long, 1.1–1.8 mm diam, sparsely covered with appressed to ascending, yellowish hairs c. 0.2 mm long; lower bract absent or lanceolate, c. 1.2 by 0.4 mm, indument as on rachis; upper bract in the upper half of the pedicel or halfway, ovate, 1.2–1.6 by 0.9–1.6 mm, densely covered with yellow hairs; flower buds globose. Flowers bisexual; sepals free or slightly connate at the base, depressed ovate, 1.1–1.7 by 2.5–3.4 mm, apex rounded, densely covered with appressed, yellow-brown hairs, persistent in fruit; receptacle 1.5–2.5 mm diam, slightly convex; petals colour in vivo unknown, 6, in two whorls, outer petals broadly ovate, 6–8 by 5.2–8.1 mm, outside and near the margins of the inside sparsely to densely covered with white-yellowish hairs, inner petals ovate to rhombic, 4.5–5.3 by 3.5–3.9 mm, outside densely covered with white-yellow hairs, inside glabrous except for the apical part; stamens 23 or 24, in three whorls, free, obovoid, 1–1.2 mm long, filaments 0.3–0.4 mm long, thecae latrorse to extrorse, connective truncate, prolonged outward, not hiding thecae, glabrous, staminodes absent; carpels 9–12, subcylindric, 1.5–1.8 by 0.4–0.5 mm, glabrous or sometimes with few hairs at the base, ovules 5 or 6, lateral, stigma elongate, obconical, 0.6–0.8 mm long, glabrous. Monocarps 3–11, yellow to orange, moniliform to subcylindric, each part subcylindric, 25–85 by 5–6 mm, slightly verrucose, glabrous or covered with few, yellowish hairs on the stipe, apex apiculate, apiculum 1–2 mm long, stipes 10–23 mm long. Seeds 1–6, subcylindric, 14–19 by 5–6 mm, ochre-brown, apex flattened to rounded, raphe not visible.

Distribution — Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Nigeria, Cameroon, Central African Republic, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Angola.

Habitat & Ecology — In primary forest, secondary forest, savanna with forest pockets and gallery forest. Altitude: 70– 1524 m. Flowering: September to May; fruiting: all year round.

Vernacular name — Sierra Leone: Jenbigbili (N.W. Thomas 1642).

Preliminary IUCN conservation status — Least concern (LC). EOO: 4 617 777 km 2, AOO: 184 km 2. This species has a very wide distribution with several collections made in protected reserves and therefore this species is currently not under threat of extinction.

Notes — 1. Monanthotaxis laurentii can easily be recognized in fruit by the long, subcylindric seeds, extra-axillary inflorescences, and the sparse indument of yellow hairs on the young branches. In flower it can be recognized by having 23 or 24 stamens in three whorls, glabrous carpels and the indument of the young branches.

2. In West Africa there are fruiting specimens in Benin, Togo and north-east Ivory Coast with fruits as M. parvifolia , i.e., with red fruits and ellipsoid seeds. However, the DNA and the leaves match M. laurentii ( Fig. 1 , clade A). Flowering material from this area is needed to verify if these specimens really belong to M. laurentii .

Figures

Map 27 Distribution of Monanthotaxis laurentii (De Wild.) Verdc. (●, O means uncertain dets).

Fig. 18 a–i. Monanthotaxis klainei (Engl.) Verdc. a. Leaves; b. flower bud seen from above; c. outer petal, inside view; d. inner petal, inside view; e. flower with petals removed; f. stamen, inside view and outside view; g. staminode; h. carpel and longitudinal section of carpel; i. fruits. — j–o. Monanthotaxis laurentii (De Wild.) Verdc. j. Flowering branch; k. outer petal, inside view; l. inner petal, inside view; m. flower with petals removed; n. stamen, outside and inside view; o. carpel and longitudinal section of carpel (a–h: Klaine 2662; i: Klaine 1539; j–o: Le Testu 4512). — Modified from Le Thomas (1969) plate 39.

Fig. 1 Bayesian 50 % majority rule consensus tree of the genus Monanthotaxis. Asterisks at nodes indicate node support, i.e., *** Strong node support, ** moderate node support, * weak node support, see Hoekstra et al. (2018). The letters A to K with adjacent black bars indicate the clades. The triangles, circles and squares represent morphological characters of the species which are of some use to distinguis the clades. Green triangles = staminodes absent, red triangles = staminodes present. Green circles = petals in one whorl, red circles = petals in two whorls, yellow circles = petals in bud basally in one whorl, at the top outer petals overlapping the inner ones. Green squares = inflorescences extra-axillary or if cauliflorous also extra-axillary inflorescences present, red squares = inflorescences axillary, supra-axillary or cauliflorous, red and green squares = both extra-axillary and axillary inflorescences present.