Monotes adenophyllus Gilg var. adenophyllus

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 : 161-164

1a. Monotes adenophyllus Gilg var. adenophyllus

= Monotes adenophyllus Gilg subsp. adenophyllus ( Verdcourt 1989: 7; Lebrun & Stork 1991: 144), syn. nov.

= Monotes delevoyi De Wildeman (1927a: 171) ; Bancroft (1935: 512; 1939a: 344) ≡ Monotes adenophyllus Gilg subsp. delevoyi (De Wild.) Duvigneaud (1959: 101 ; 1961: 413); Catarino et al. (2013: 266); Lebrun & Stork (1991: 144); White (1962: 263; fig. 46C). Type:—D.R. CONGO. Masolwa, 17 December 1921, Delevoy 524 (holo-: BR! [barcode BR0000008891600]), iso-: BRLU!), syn. nov.

= Monotes verdicki De Wildeman (1927a: 183 , 1927b: 57); Bancroft (1935: 512; 1939a: 346). Type:—D.R. CONGO. Lukafu, February 1900, Verdick 374 (holo-: BR! [barcode BR0000008899576]), syn. nov.

= Monotes hutchinsonianus Exell (1932: 219) ; Bancroft (1937: 138; 1939a: 353); Lebrun & Stork (1991: 144); Catarino et al. (2013: 269); Duvigneaud (1949: 57); Figueiredo & Smith (2008: 67). Type:— ANGOLA. Malange, 27 December 1930, Gossweiler 9581 (BM! [barcode BM000603406], BRLU (fragm.)!, COI!, K! [barcode K000240349], LISC! [barcode LISC019573]), syn. nov.

= “ Monotes pwetoensis Robyns ” in schedis, unpublished designation ( Bancroft 1939a: 367), syn. nov.

= Monotes magnificus Gilg var. glabrescens Duvigneaud (1949: 54) . Type as Monotes delevoyi , syn. nov.

= Monotes magnificus Gilg var. paucipilosus Duvigneaud (1949: 55 , Pl. 13: b,c). Lectotype (designated here):—D.R. CONGO. Katanga, Kinda , forêt claire à Brachystegia sur sable argileux blanc, 5 August 1948, Duvigneaud 1131M (lecto-: BRLU! [barcode BRLU0000090022302], isolecto-: BRLU! (4 sheets)), syn. nov.

= Monotes adenophyllus Gilg subsp. subfloccosus Duvigneaud (1959: 102) ; Duvigneaud (1961: 414). Type :— ZAMBIA. Northern Prov., Fort Rosebery-Luwingu road, 19 May 1931, Stevenson 247/31 (holo-: FHO! [barcode 00006099], iso-: K!, NDO), syn. nov .

Diagnosis:— Leaf blade concolorous; areoles of lower surface of leaf glabrous or with a few stellate hairs; reticulum of lower leaf surface with hairs 0.2–1 mm long, shorter than or equalling areole diameter and not hiding areoles.

Illustrations: — Figs. 3A , 4A , 5A , 6B–D .

Distribution in D.R. Congo: —Widespread in Upper Katanga, though less common than var. homblei .

Distribution elsewhere: — Angola, Tanzania, Zambia.

Habitat and ecology: —Miombo woodland and bushy savannah, often on shallow lateritic or skeletic schistose substrate.

Vernacular names: —Ki(m)papa (Bemba).

Other representative specimens examined:—D.R. CONGO. Upper Katanga: Plaine de la Lufira, au N de Lukafu, forêt claire à Julbernardia globiflora , sur terre rose, 17 July 1948, Duvigneaud 1259M (BRLU!); Fungurume, forêt enrochée à Brachystegia bussei , 1956, Duvigneaud & Timperman 2619 (BRLU!); territ. Lubudi, Kanoni, forêt à Brachystegia bussei sur macigno, 3 June 1957, Duvigneaud 3378M (BRLU!); Likasi, colline boisée de la série des mines à Julbernardia paniculata et Brachystegia utilis , 18 June 1957, Duvigneaud 3586M (BRLU!); Katofio (Kilwa), forêt sèche à Julbernardia paniculata , sol beige sur cuirasse latéritique, 1957, Duvigneaud 3625M (BRLU!); Mpwa, 10 km N Tinika, steppe arbustive suffrutescente à Brachystegia nain sur schistes psammitiques, 1957, Duvigneaud 3639M (BRLU!); Lukunki, savane à Themeda sur pente rocheuse calcaire, 11 January 1960, Duvigneaud 4998M (BRLU!); 20 km N de Bunkeya, haute savane arbustive sur dalle latéritique d’alluvions anciennes, 14 January 1960, Duvigneaud 5044M (BRLU!); Muvulu, verger à Monotes sur schiste à schistosité horizontale, 15 January 1960, Duvigneaud 5059M (BRLU!); 20 km S Kiubo, verger à Monotes adenophyllus , 17 January 1960, Duvigneaud 5112M (BRLU!); Kundelungu, under trees, 13 March 1908, Kassner 2605 (BM!); 6 km NE Gombela, forêt claire, 26 May 1984, Malaisse 13000 (BR!); Environs de Pweto, 1926, Robyns 1954 (K!); 26 km de Jadotville vers Kolwezi, alluvions assez récentes, exondées, anciennement cultures, savane à hautes graminées, 17 April 1958, Schmitz 5971 (BR!); Kampinda, km 24 route Balanga-Musosa, savane arborée, alt. 980 m, 17 June 1957, Symoens 4058 (BRVU!); Upemba, Vandenbrande K9 (BR!).

Discussion:— Forms with leaves showing a sparsely pilose lower reticulum have usually been recognized as Monotes adenophyllus subsp. delevoyi , but Verdcourt (1989) already questioned the status of that taxon. However, variation in density and length of hairs on the reticulum is continuous and we have not been able to set the objective limits of “ delevoyi ” and conclude that this taxon cannot be maintained.

Monotes hutchinsonianus , an enigmatic species said to be endemic of Angola, is a large-leaved form, with a deeply cordate leaf base and long inflorescences. Such forms are not rare in Upper Katanga (e.g. Duvigneaud & Timperman 2123 (BRLU!); Huart 11 (BR!); Malaisse 11286 (BR!)); they are linked to smaller-leaved forms by many intermediates. Thus, M. hutchinsonianus is here merged with M. adenophyllus var. adenophyllus . Bancroft (1937) already suggested that M. hutchinsonianus and M. delevoyi might be conspecific. Significantly, the type specimen of M. hutchinsonianus shows an extremely variable leaf shape, some of the leaves being very close to those of the type specimen of M. glandulosus (oblong-ellipitic, obtuse at base and rounded at apex) and others to M. adenophyllus (broadly ovate, cordate at base) (see e.g. the isotypes, barcode BM000603406 and barcode LISC019573). Robyns 1954, the specimen carrying the designation “ M. pwetoensis Robyns ” (in schedis, unpubl.) from Katanga was ascribed to M. hutchinsonianus by Bancroft and to M. adenophyllus by Duvigneaud, illustrating that species limits in the M. glandulosus group are very difficult to set.

A morph of Monotes adenophyllus Gilg said to have a special type of hairs giving a subfloccose appearance to the lower surface of the leaf has been recognized as subsp. subfloccosus by Duvigneaud, but it is very difficult to define and is therefore not recognized here.

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 6. Colour photographs of leaves: Monotes adenophyllus. A. M. adenophyllus var. homblei (Duvigneaud 4570M2); B–D. M. adenophyllus var. adenophyllus (Duvigneaud 5044, Duvigneaud 5112M, Duvigneaud 1393). Scale bar = 5 cm.