Monanthotaxis confusa P.H.Hoekstra, 2021

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 : 140-142

15. Monanthotaxis confusa P.H.Hoekstra , sp. nov. — Fig. 9a–d ; Map 11

Monanthotaxis confusa has unisexual flowers and can be distinguished from other species by the staminate flowers with 19–22 stamens in two whorls and a lack of staminodes.The staminate flowers of M. mortehanii and M. glomerulata are unknown, but it can be distinguished from M. mortehanii by the very short appressed hairs c. 0.1 mm long on the pedicels,while M. mortehanii has erect, 0.4–0.6 mm long hairs on the pedicels of the pistillate inflorescence; it differs from M. glomerulata in the number of carpels (> 100 vs 80–95), the petiole size (7–10 mm vs 5–7 mm long, the length of the sympodial rachis of the pistillate inflorescences (5–15 mm vs <5 mm) and the length of flowering pedicels (21–25 mm vs <10 mm). — Type: G.C.C. Gilbert GCC14442 (holo WAG (WAG.1587477);iso BR0000013186098), Democratic Republic of the Congo, Bandundu, Bankaie, Lac Leo II, 14 July 1953. Paratypes: J.H.P.A. Ghesquière 6665 (K, P), Democratic Republic of the Congo, Nord-Kivu,nord de Rutshuru, forêt de Makwera, 1300 m, 29 May 1938; J.­P.A. Lebrun 6134 (BR,K, P), Democratic Republic of the Congo,Kasai-Oriental,Katakokombe,

mm

Nov.1932; J. L. P. Louis 5882 ( B, BR, K, P), Democratic Republic of the Congo, Orientale , Isangi, Yangambi, 470 m , 29 Aug. 1937; J. L. P. Louis 7000 ( BR, C, MO, US), Democratic Republic of the Congo, Orientale, Yangambi, 470 m , 13 July 1937; J. L. P. Louis 9282 ( BR, FHO, K, P), Democratic Republic of the Congo, Orientale, route d’Isangi, 470 m , 9 May 1938; J. L. P. Louis 9966 ( B, BR), Democratic Republic of the Congo, Orientale, Yangambi, 470 m ; J. L. P. Louis 12169 ( BR, C, MO, US), Democratic Republic of the Congo, Orientale , Isangi, Yangambi, 470 m , 25 Oct. 1938.

Etymology. Named confusa because this species has been confused with Monanthotaxis cauliflora . The fact that Le Thomas (1969) described and depicted a staminate flower of M. confusa as M. cauliflora added to this confusion.

Growth form unknown ; young branches dark brown, covered with brown hairs c. 0.1 mm long, becoming glabrous; old branches dark brown to blackish. Leaves: petiole 7–10 mm long, 1.5–1.9 mm diam, grooved, indument as on branches; lamina ovate to obovate or narrowly so, 13.3–20.7 by 5.5–8.5 cm, 1.8–2.9 times longer than wide, chartaceous, not punctate, above glabrous, but primary vein covered with erect, whitish hairs c. 0.3 mm long, below covered with appressed hairs 0.1–0.2 mm long, base rounded, with thickened black margin, apex acute, secondary veins 13–16 per side, straight at end curving slightly upwards, tertiary venation percurrent. Flowers unisexual. ♂ Inflorescences axillary or ramiflorous, composed of 1–7-flowered, fascicle-like rhipidia; sympodial rachis 2–8 mm long, densely covered with appressed, dark brown hairs; pedicels 3–8 mm long, 0.8–0.9 mm diam, densely covered with appressed to ascending, reddish brown hairs; lower bracts broadly to depressed ovate, 0.5–1 by 0.7–0.9 mm, indument slightly more dense as on rachis; upper bract broadly ovate, 0.7–0.9 by 0.8–1 mm, indument as on lower bract, flower buds broadly ovoid; sepals free, broadly ovate, 1–1.7 by 1.2–1.5 mm, densely covered with appressed hairs; receptacle 1–2 mm diam, convex; petals colour in vivo unknown, 6, in two whorls, free, outer petals depressed ovate, 2.5–3.6 by 3.3–4.7 mm, outside densely covered with dark brown hairs 0.1–0.2 mm long, inside densely covered with yellow-brown hairs <0.1 mm long, inner petals elliptic, 1.6–1.9 by 0.8–0.9 mm, outside and inside densely covered with yellow-brown, very short hairs; stamens 19–22, in two whorls, free, oblong, 0.7–0.8 mm long, filaments c. 0.1 mm long, thecae extrorse, connective truncate, connective and filaments hairy, staminodes absent. ♀ Inflorescences cauliflorous, many-flowered; sympodial rachis 5–15 mm long, covered with brownish hairs c. 0.1 mm long; bracts ovate, 1.1–1.7 by c. 1 mm, densely covered with brownish hairs; flower buds ovoid; flowering pedicels 21–25 mm long, 0.8–0.9 mm diam, indument as on rachis; sepals free, broadly ovate to spathulate, 2–3 by 1.5–3 mm, densely covered with brownish hairs; receptacle to 2.5 mm high, c. 1.5 mm diam, convex; petals colour in vivo unknown, 6, in two whorls, free, outer petals broadly ovate, 6–6.5 by 6.5–7.5 mm, outside covered with dark hairs c. 0.1 mm long, inside papillate; inner petals obovate, c. 3 by 2 mm, both sides densely covered with yellowish papillae; carpels c. 128, ellipsoid to rhombic, 1.1–1.3 by 0.5–0.6 mm, densely hairy, ovules 6, lateral, stigma globose and to 0.2 mm long in the middle of the flower, elongate and to 0.4 mm long in the outer whorls, glabrous. Monocarps up to at least 5, colour in vivo unknown, ellipsoid to narrowly ellipsoid, at least 10 mm long, 6 –7 mm wide, slightly verrucose, sparsely covered wtih appressed, short hairs, apex rounded to slightly apiculate, apiculum to 0.5 mm long, stipes c. 5 mm long. Seeds at least 3, ellipsoid, 8–9 by c. 6 mm, reddish brown, with ends flattened, with a c. 4 mm long funiculus, raphe visible.

Distribution — Democratic Republic of the Congo (Bandundu, Kasai-Oriental, Nord-Kivu, Orientale).

Habitat & Ecology — In terra firme forest and inundated forest. Altitude: 300–1300 m. Flowering: July to September; fruiting: October.

Preliminary IUCN conservation status — Endangered (EN): B2ab(iii). EOO: 295 065 km 2, AOO: 20 km 2. This species is only known from 9 collections in 4 localities and was last collected in 1953. Field work is needed to verify if this species still exists.

Note — The specimens of M. confusa were previously identified as M. cauliflora . The staminate flowers are very different from that species, they have 19–22 stamens and no staminodes (vs 6 stamen and 12–13 staminodes), whereas the pistillate flowers have twice the number of carpels compared to M. cauliflora . The description of the staminate flowers of M. cauliflora in Le Thomas (1969) was based on the staminate flowers of J.­P.A. Lebrun 6134, which is now included in M. confusa .

Figures

Map 11 Distribution of Monanthotaxis confusa P.H.Hoekstra (●, O means uncertain det) and M. congolana (Boutique) P.H.Hoekstra (■).

Fig. 9 a–e. Monanthotaxis confusa P.H.Hoekstra. a. Staminate flowering branch; b. staminate flower,outer petal,inside view; c. staminate flower, inner petal, inside view; d. staminate flower with petals removed; e. stamen, outer and side view. — f–n. Monanthotaxis diclina (Sprague) Verdc. f. Staminate flowering branch; g. staminate flower with one outer petal removed; h. staminate flower inner petal, inside view; i. stamen, outside and inside view; j. staminate flower staminode; k. pistillate flower, outer petal, inside view; l. pistillate flower, inner petal, inside view; m. carpel and longitudinal section of carpel; n. fruits. — o–s. Monanthotaxis glomerulata (Le Thomas) Verdc.o. Pistillate inflorescence; p. pistillate flower with one outer petal removed;q. pistillate flower, outer petal,inside view; r. pistillate flower, inner petal, inside view; s. carpel and longitudinal section carpel (a–e: Lebrun 6134; f–j: Klaine 2881; k–m: Klaine 1382; n: Klaine 404; o–s: Le Testu 8700). — Modified from Le Thomas (1969) plate 38.