Monotes autennei Duvigneaud (1958: 183)

Meerts, Pierre, Rougelot, Quentin & Sosef, Marc, 2017, Revision of the genus Monotes (Dipterocarpaceae) in D. R. Congo, with implications for Angola and its distinction from Marquesia, Phytotaxa 308 (2), pp. 151-205 : 171-172

3. Monotes autennei Duvigneaud (1958: 183)

Type: —D.R. CONGO. Kahundu, Dilolo, forêt claire à Brachystegia boehmii , 23 May 1957, Duvigneaud 3267MI (holo-: BRLU! [barcode BRLU0000090020735], iso-: BRLU! (3 sheets)).

Tree up to 17 m high; branchlets shortly puberulous to densely pubescent. Leaf: petiole 10–25 mm long, very thick (3–3.5 mm in diameter); blade broadly elliptic, obovate, sometimes suborbicular, (7–)12–18(–22) × (5–)9–12(–14) cm, leathery, broadly cordate to rounded at the base, obcordate-bilobate or deeply emarginate at the apex, typically with the apical sinus deeper than the basal one, often with extra leaf-glands in the axils of the lateral nerves; lateral nerves 12–15 pairs, slightly incurved, some of them bifurcate near the apex, nerves and bifurcations reaching the margin of the leaf; upper surface slightly scaberulous with short straight hairs 0.15–0.3 mm long in fascicles of 2–8 on small white cushions, finally glabrous; lower surface greyish- or fulvous-pubescent (sometimes glabrescent when old), with relatively long curved hairs mixed with fasciculate ones, and with the interreticular areoles densely to sparsely covered with minute stellate hairs; midrib very thick and prominent beneath; veins and reticulation very prominent and forming deep cavities. Inflorescences, flowers and fruits as in M. katangensis .

Illustrations: — Figs. 3D , 4D , 5B,C , 7A,B , 13.

Distribution in D.R. Congo: —Widespread in Upper Katanga, apparently more frequent in the west.

Distribution elsewhere: — Zambia. Restricted distribution.

Habitat and ecology: —Miombo woodland; mixed high woodlands with Marquesia acuminata and M. macroura on grey compact soil; chipya on Kalahari sand.

Other representative specimens examined:—D.R. CONGO. Upper Katanga: 20 km E of Kasagi, territ.Kisenge, forêt à Marquesia sur terre grise compacte à petites termitières, Duvigneaud & Timperman 2317Mo1 (BRLU!); 15 km N of Dilolo, forêt claire de plateau à Marquesia sur sol gris, 21August 1956, Duvigneaud & Timperman 2424 (BRLU!); Tshisenge, 17 km N of Dilolo, forêt claire à Marquesia sur sol gris compact, 1957, Duvigneaud 2428M (BRLU!); Dembo de la Lufupa, forêt claire de bordure à Brachystegia longifolia et Cryptosepalum pseudotaxus, Duvigneaud & Timperman 2541 (BRLU!); Kalongwe, brousses denses avec Monotes caloneurus , 9 May 1957, Duvigneaud 3090M (BRLU!); Kolwezi, Colline D, forêt claire sur roches siliceuses cellulaires, 13 June 1957, Duvigneaud 3494M; Nzilo, forêt verger sur terre compacte, 14 June 1957, Duvigneaud 3516M (BRLU!); Kyamandjizi, forêt claire, 8 October 1981, Malaisse 11939a (BR!); route Nzilo-Le Marinelle, km 1.5, crête au dessus du barrage, formée de quartzite et de quartzophyllades, 21 September 1958, Plancke 111/1532 (BRLU!).

Discussion:— Monotes autennei is generally easy to recognize by its large bilobed leaves with fasciculate hairs on the upper surface. Many specimens had been misidentified as M. katangensis or M. magnificus . Intermediates with M. katangensis are frequent (see note under that species). Some collections have a rounded leaf apex and ovate-elliptic leaves (Desenfans 4012 (BRLU!)).

References:— Duvigneaud (1961: 414); Lebrun & Stork (1991: 144); Meerts (2016: 222).

Figures

FIGURE 3 A–H. Details of lower surface of the leaf.A. Monotes adenophyllus var. adenophyllus (Duvigneaud 5112). B. M. adenophyllus var.homblei (Duvigneaud 4601). C. M.africanus (Duvigneaud 2006). D.M.autennei (Duvigneaud 5260). E.M.dasyanthus var.dasyanthus (Duvigneaud & Timperman 2341). F. M.dasyanthus var. heterotrichus (Duvigneaud 1141). G. M. dasyanthus var. mutetetwa (Duvigneaud 950). H. M. doryphorus (Duvigneaud 5267).

FIGURE 4 A–H. Details of upper surface of the leaf.A. Monotes adenophyllus var.adenophyllus (Duvigneaud 5044). B. M.adenophyllus var.homblei (Duvigneaud 4570). C. M.africanus(Duvigneaud 2006). D. M.autennei(Plancke 111/1532). E.M.dasyanthus var.dasyanthus (Duvigneaud & Timperman 2341). F. M. dasyanthus var. heterotrichus (Duvigneaud 4493). G. M. dasyanthus var.mutetetwa (Duvigneaud 950). H. M. doryphorus (Duvigneaud 5267).

FIGURE 5 A–H. SEM photographs of leaf blade surfaces for 12 members of Monotes. A. M. adenophyllus var. adenophyllus, lower surface (Delevoy 524, type of M. delevoyi). B. M. autennei, lower surface (Duvigneaud 3267 (type of M. autennei)). C. M. autennei, upper surface (Duvigneaud 3267). D. M. hypoleucus var. angolensis, lower surface (Duvigneaud 950M2, type of M. oxyphyllinus). E. M. hypoleucus var. angolensis, upper surface (Duvigneaud 950M2). F.M. hypoleucus var. caloneurus, lower surface (Schmitz 1332 (type of M. schmitzii)). G. M. hypoleucus var. caloneurus, upper surface (Schmitz 1332 (type of M. schmitzii)). H. M. hypoleucus var. hypoleucus, lower surface (Welwitsch 1036 (type of M. hypoleucus)).

FIGURE 7. Colour photographs of leaves: Monotes autennei. A. Duvigneaud 5260, B. Duvigneaud & Timperman 2545. M. katangensis: C. Duvigneaud & Timperman 2233; D. Duvigneaud & Timperman 2641. Scale bar = 5 cm.