Monotes hypoleucus (Oliv.) Gilg var. hypoleucus

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 : 183-184

9a. Monotes hypoleucus (Oliv.) Gilg var. hypoleucus

= Monotes kapiriensis De Wildeman (1927a: 175 ; 1927b: 56); Bancroft (1937: 141; 1939a: 345). Lectoype (designated here):—D.R. CONGO. Vallée de Kapiri, versant plateau, February 1913, Homblé 1228 (lecto-: BR! [barcode BR0000008891617], iso-: BR! [barcode BR0000008891334]).

Small tree or more often a stunted shrub; branches shortly grey-tomentose, glabrescent. Leaf: petiole 9–21 mm long, ca. 2 mm in diameter; blade broadly elliptic or ovate-elliptic to obovate-elliptic, (10–)12–16(–20) × (6–)7–9(–13) cm, base rounded to slightly cordate, apex rounded to emarginate, strongly discolorous; secondary nerves in (9–)13–17 pairs, fulvous-brownish below, contrasting with indumentum, of short crispate fulvous hairs, soon glabrescent, tertiary nerves slightly impressed above; upper surface generally brownish in herbarium, puberulent with more or less sparse persistent indumentum of more or less flexuous thin hairs 0.1–0.15 mm long in fascicles of 2–6, and yellow spherical glands; lower surface whitish to cream or beige, with thick dense indumentum of tangled woolly hairs, masking reticulum and areoles, with longest hairs> (0.5–) 0.8 mm long, indumentum eventually becoming grayish and thinner in old leaves. Inflorescence composed of many-flowered long-pedunculated axillary cymes 5–8 cm long, peduncle densely tomentose, beige. Flower: pedicel 1–3 mm long, sepals ovate ca. 3 mm long, petals ca. 9 mm long. Fruit ca. 10–15 mm in diameter, spherical, subapiculate; wings elliptic to narrowly obovate, not unguiculate, 2.5–5 × 1–2 cm, pale brown.

Illustrations: — Figs. 3L , 4K , 5H,I .

Distribution in D.R. Congo: —Widespread in Kwango; rare in Katanga (Biano, Kundelungu).

Distribution elsewhere: — Angola, Zambia (first record for that country: Mutimushi 1857 (K!)).

Habitat and ecology: —In Kwango in mixed dry semi-evergreen forests of the alliance Berlinio-Marquesion, especially the association with Marquesia macroura and Uapaca nitida , subassociation with Berlinia giorgii ; degraded forests (« Matumbi ») in contact with the steppic savannah ( Devred 1957); miombo forests; in Upper Katanga in shrubby savannahs on Kalahari sand.

Vernacular names: —Kipapa (Kiluba), mupampa, mupemba (Kiyaka).

Other representative specimens examined:—D.R. CONGO. Kasaï (Kwango): Route Mawanga-Imbela, km 13, forêt claire, 19 July 1975, Breyne 2611 (BR!); Vers Munene, savane boisée, 14 April 1953, Callens 1158 (BR!); Haute-Muniungu, savane boisée, 14 April 1953, Callens 1159 (BR!, KISA); Kiwangala, forêt sèche, 22 April 1953, Callens 2952 (BR!); Bwana Mutombo, Matumbi, 7 July 1952, Callens 3126 (BRLU!, KISA); région de Imbela, forêt sèche, 2 May 1953, Callens 4121 (BR!); région de Imbela, savane boisée, 2 May 1953, Callens 4122 (BR!, KISA); Mobanga, Mikondo, sous-bois, 19 March 1955, Devred 1673 (BR!); Ingolobo (entre Popobakata et Munene), bosquet à Monotes , Uapaca , Berlinia , 27 April 1948, Duvigneaud 774M (BRLU!); Entre Ingolobo et Munene, steppe sableux reverdi après l’incendie, 27 April 1948, Duvigneaud 779M (BRLU!); Kenge, 30 km N de Munene, forêt claire à Brachystegia wangermeeana-Uapaca, 1 May 1948, Duvigneaud 822 (BRLU!); Kahemba, forêt claire autour de la mission, 30 May 1948, Duvigneaud 949M (BRLU!); Kahemba, forêt de savane à Brachystegia sur sable du Kalahari, 5 October 1948, Robyns 3727 (BR!, WAG!). Upper Katanga: Kyongwe (Relevé 142), 1300 m, forêt claire, 15 May 1953, Desenfans 3226 (BRLU!); Steppe arbustive près de Lusinga (Kibara), 1650 m, Lisowski, Malaisse & Symoens 4412 (POZG!).

Discussion:— Monotes kapiriensis was synonymized with M.discolor by Bancroft (1939a) and with M.hypoleucus by Duvigneaud (1949). See note under var. discolor . Some collections from Kwango have very large leaves reminiscent of var. discolor , however they have fruits 12–15 mm in diameter and leaves with a puberulent upper surface (Callens 4122; Devred 1673).

Intermediates with var. caloneurus exist: Duvigneaud 4667M (BRLU!).

Hiern (1896: 62) correctly attributes this variety to Oliver by citing “ Vatica africana Welw. ex Oliv. var. hypoleuca Oliv. ”. Oliver, in the Flora of Tropical Africa (Oliver 1868: 173) wrote: “ Vatica africana, Welw. in Linn. Trans. xxvii (ined.) t. 5”, clearly indicating that he did not want to publish the name. However, according to the rules of the International Code of Nomenclature ( McNeill et al. 2012) the correct authority for Vatica africana is indeed Welw. ex Oliv., or just Oliv.

References:— Bancroft (1937: 140; 1939a: 379); Catarino et al. (2013: 269); De Wildeman (1913a: 42; 1921: 133; 1927a: 175); Durand & Durand (1909: 48); Duvigneaud (1949: 49); Engler (1921: 520); Figueiredo & Smith (2008: 67); Gilg (1908b: 288); Hiern (1896: 62); Lebrun & Stork (1991: 144).

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)).