Clerodendrum tanganyikense Baker (1895a: 71

Meerts, Pierre, 2023, The genus Clerodendrum (Lamiaceae) in the flora of Central Africa (D. R. Congo, Rwanda, Burundi), Phytotaxa 594 (1), pp. 1-42 : 31-32

23. Clerodendrum tanganyikense Baker (1895a: 71 ; 1900: 298); Thomas (1936: 68); White (1962: 367); Verdcourt (1992: 111); Lebrun & Stork (1997: 513); Fernandes (2005: 111).

Type:— TANZANIA. Fwambo , Lake Tanganyika, 1894, Carson 52 (holotype: K000192926) .

= Clerodendrum thonneri Gürke (1900: 292) ; Baker (1900: 517); Durand & Durand (1909: 441); De Wildeman (1909: 137; 1912b: 132); Thomas (1936: 68); Lejoly et al. (2010: 295). Type:—D.R. CONGO. Boyangi, 400 m, 7 September 1896, Thonner 69 (holotype: BR0000008978592!), synon. nov.

= Clerodendrum dubium De Wildeman (1914: 144 ; 1921: 166); Thomas (1936: 67) ≡ Clerodendrum tanganyikense var. dubium (De Wild.) Moldenke (1953a: 177 ; 1980: 219). Type:—D.R. CONGO. Upper Katanga, Elisabethville [Lubumbashi], 7 April 1912, Bequaert 322bis (holotype: BR0000008979254!).

= Clerodendrum lupakense Moore (1919: 247) . Type :—D.R. CONGO. Lupaka river, 6 February 1908, Kassner 2458 (in part!) (lectotype designated here: BM000798639 ).

= Clerodendrum consors Moore (1919: 248) ; Thomas (1936: 68). Type:—D.R. CONGO. Lupaka river, 6 February 1908, Kassner 2458 (in part!) (lectotype designated here: BM000798638).

= Clerodendrum bingaense Moore (1919: 248) ; Thomas (1936: 68); Moldenke (1985c: 199); Lebrun & Stork (1997: 510). Type:—D.R. CONGO. Binga, Kassner 2627 (holotype: BM000798637; iso-: HBG512168).

= Clerodendrum tanganyikense var. microcalyx Moldenke (1953a: 177 ; 1980: 219); Schmitz (1963: 391). Type:—D.R. CONGO. Munama. 8 March 1926, Robyns 1577 (lectotype designated here: BR0000008979414!).

= Clerodendrum bequaertii De Wildeman (1914: 144 ; 1921: 165); Thomas (1936: 67); Schmitz (1963: 254); Lebrun & Stork (1997: 510) ≡ Clerodendrum tanganyikense var. bequaertii (De Wild.) Moldenke (1953a: 177 ; 1980: 219) not Clerodendrum bequaertii De Wildeman (1920b: 185) . Type:—D.R. CONGO. Upper Katanga, Elisabethville [Lubumbashi], Bequaert 322 (lectotype designated by Thomas (1936): BR0000008979445! & BR0000008979360!).

Suffrutex, shrub, sarmentose shrub or liana up to 6 m. Stem puberulent, pubescent or hispid, at least in the uppermost part and at nodes (beige-fulvous hairs), pale brown, with pale lenticels, persistent petiole bases ca. 2 mm. Leaves occasionally 3-whorled, petiole 0.5–4.5 cm, canaliculate, pilose; lamina obovate to elliptic, more rarely ovate to suborbicular, generally somewhat asymmetric, 5–13(–16) × 2.5–8.0 cm, base cuneate, obtuse to rounded, apex acuminate, or rounded and abruptly acuminate, 5–7 veins on either side, generally impressed, upper surface dark green, dull, subglabrous, reticulum not prominent, lower surface with pubescence extremely variable, from almost glabrous to brown-tomentose on the whole surface, most often spreading-pilose on main veins, sometimes only at the base of midvein; margin entire to undulate or crenate, occasionally crispate (in the most pubescent forms). Inflorescence: 4–9-flowered cymules on 7–10 mm long peduncle, either solitary in leaf axils, more often grouped in thyrses, either terminal on leafy shoots, or lateral on old defoliated twigs, rachis shortly pubescent to hispid, with 5–6 nodes, bracts linear to narrowly obovate, sometimes foliaceous, peduncle 2–16 cm, more or less pubescent; flower: pedicel 2–4 mm, shortly pubescent to hispid, bracteoles linear, fulvous puberulent; calyx tubular to narrowly campanulate, (3–) 5–8 mm long, 3–4 mm wide at throat, glabrous, puberulent, pubescent, or, more rarely tomentose, lobes ovate to triangular, 1–1.5(–2) mm long; corolla scented, tube (10–) 13–20 mm, glabrous or very rarely pilose, lobes 3–4 mm long, gland-dotted; stamens exserted 6–8 mm, anther ca. 1 mm long. Fruit 11 × 8 mm, subtended by cupuliform calyx 11 × 10 mm, whitish, striate.

Distribution in Central Africa:—D.R. Congo, Rwanda, Burundi.

Distribution elsewhere:— Cameroon, Uganda, Tanzania, Zambia, Angola.

Habitat:—Savannah, wooded savannah, dry semi-deciduous woodland, dry evergreen forest, more rarely rainforest, mountain forest, riparian forest; up to 2480 m.

Selection of representative specimens:—D.R. CONGO. Kasaï: Kambangu. Galerie de la Kaziala, 11 February 1952, Callens 3243 (BR!); Muetshi, 70 Km WNW of Lusambo, 1982, Casier 219 (BR!). Forestier Central: Eala, 11 August 1932, Corbisier-Baland 1644 (BR!); Bokuma, 5 March 1941, Hulstaert 125 (BR!); Eala, 1 June 1905, M. Laurent 743 (BR!). Lac Albert: Djugu, 1 October 1957, Deville 125 (BR!). Lacs Edouard et Kivu: Prov. Twangiza, Mwama River Valley near Kashane, 17 April 2008, Bytebier & Luke 3097 (BR!, EA); Plaine de la Ruzizi, January 1950, Germain 5820 (BR!), Mulungu (Sud Kivu), 4 May 1959, Pierlot 2870 (BR!). Haut-Katanga: Mont Mukwen, 15 March 1986, Lumbu Simbi 5 (BR!, WAG); Biano, 30 January 1984, Schaijes 2224 (BR!, with photo)); Elisabethville [Lubumbashi], December 1922, de Giorgi 336 (BR!); Kilubi, ferme Pirard, March 1946, Quarré 7760 (BR!).— BURUNDI. Lacs Edouard et Kivu: Matana, territ. Bururi, 3 February 1968, Lewalle 2752 (BR!); Territ. Muramvya. Mont Teza, 9 April 1972, Lewalle 6699 (BR!); Mont Teza, 19 April 1980, Reekmans 8925 (BR!, WAG); Bugarama, 25 January 1981, Reekmans 9526 (BR!, WAG). Rwanda-Burundi: Territ. Kitega. Chefferie Bweru, Karuzi, 26 March 1958, van der Ben 1994 (BR!).— RWANDA. Lacs Edouard et Kivu: Forêt de Nyungwe , environs de Gahate, 12 May 1971, Bouxin 688 (BR!); Route Kibuye-Cyangugu, env. De Gishyita (± 30 km de Kibuye), 13 February 1980, Bridson 396 (BR!, WAG); 20 km from Gatumba to Kibuye, 15 February 1972, Troupin 14436 (BR!). Rwanda-Burundi: Rubona, 24 December 1958, Michel 5970 (BR!); Entre Nyabisindu et Gitwe, 10 March 1973, Troupin 14570 (BR!).

Notes:—1. C. tanganyikense is very closely related to C. silvanum (see notes under the latter species) and intermediates are occasionally found (e.g. Burundi: Reekmans 10055; D.R. Congo: Christiaensen 559, Hart 1681, Liben 2597). Clerodendrum thonneri G ü rke has been synonymized with C. silvanum in recent databases. However, in the circumscription of C. tanganyikense and C. silvanum followed in the present work, Clerodendrum thonneri is closer to Clerodendrum tanganyikense owing to the pubescent petiole, and the synonymy is changed accordingly.

2. Inflorescence architecture and position, leaf shape and pubescence are very variable in this species. Calyx indumentum is also very variable, from wholly glabrous to almost tomentose. The most pubescent forms occur in Katanga (“ var. dubium ”), but variation is continuous and this variety is not recognized here.

3. Corolla tube is most often glabrous, but specimens with sparsely pilose corolla tube occasionally occur in Katanga (e.g. Kipopo, 10 March 1985, Breyne 4912 (BR!); Route Lubumbashi-Likasi, km 12, 18 February 1970, Lisowski 27284 (BR!); Keyberg, February 1937, Quarré 4756 (BR!); Poste de Kasenga , 55 km NE Lubumbashi, 11 March 1984, Schaijes 2252 (BR! with photo); they correspond to Clerodendrum bequaertii De Wild. ( De Wildeman 1914, not De Wildeman 1920!) but this taxon is not recognized here.

Lectotypification of Clerodendrum consors Moore and Clerodendrum lupakense Moore. Clerodendrum lupakense and Clerodendrum consors were described at the same time ( Moore 1919), based on the same gathering (Kassner 2458), in which Moore recognized two new species, based on spurious differences, as already noted by Thomas (1936). The type materials are kept in BM, E and K; however, only BM holds two sheets to which a copy of the protologue is attached ( C. consors: BM 000798638; C. lupakense: BM 000798639); I designate these two sheets as the lectotypes of C. consors and C. lupakense , respectively. The duplicates in E (E00193473) and K (K000192847) are labelled “ C. consors ”, but it is unclear if they have been seen by Moore.

Lectotypification of Clerodendrum tanganyikense var. microcalyx Moldenke. Moldenke (1953a) indicated Robyns 1577 as the type. This collection corresponds to three sheets in BR, one sheet in NY, and one sheet in WAG. Only one of them (BR 0000008979414) bears a determination label “ var. microcalyx ” by Moldenke and shows the short calyx described in the protologue; it is designated here as the lectotype. The other two sheets bear a determination label by Moldenke as “ var. bequaertii ” (BR 0000008979438 and BR 0000008979469) and should therefore be excluded; the specimens in WAG ( WAG1718465 ) and NY ( NY00137393 ) depart from the protologue in having a long calyx and should be excluded.