Clerodendrum formicarum Gürke (1893: 179)

Meerts, Pierre, 2023, The genus Clerodendrum (Lamiaceae) in the flora of Central Africa (D. R. Congo, Rwanda, Burundi), Phytotaxa 594 (1), pp. 1-42 : 15-17

10. Clerodendrum formicarum Gürke (1893: 179) ; Durand & Schinz (1896: 223); Baker (1900: 297); De Wildeman (1910a: 401; 1910b: 255; 1912b: 91; 1920b: 167; 1921: 166; 1922: 262); Durand & Durand (1909: 438); Thonner (1915: 470, pl. 133); Thomas (1936: 74); Robyns (1947: 146); Huber (1963: 444), Malaise (1985: 274); Verdcourt (1992: 116); Lebrun & Stork (1997: 511); Fernandes (2005: 113); Hawthorne & Jongkind (2006: 422); Bloesch et al. (2009: 626); Lisowski (2009: 364); Lejoly et al. (2010: 294); Latham & Konda ku Mbuta (2010: 97); Pollard (2022: 25).

Type:— SOUTH SUDAN. Ghasal-Quellen Gebiet, lande der Monbuttu, 10 Apr. 1870, Schweinfurth 3641 (lectotype: B†, designated by Thomas (1936), isolecto-: K000192899) .

= Clerodendrum triplinerve Rolfe in Schumann et al. (1893: 87); White (1962: 367). Type:— ANGOLA. Malange, Marques 50 (lectotype designated here: BR0000008715463!).

= Clerodendrum lujaei De Wildeman & Durand (in Durand & De Wildeman 1899b: 213); Durand & Durand (1909: 439); De Wildeman (1912b: 91). Type:—D.R. CONGO. Sona Gunga, 29 November 1898, Luja 104 (holotype: BR0000016593862!; iso-: BR0000016593879!)

= Clerodendrum yaundense Gürke (1900: 297) ; Baker (1900: 516); Durand & Durand (1909: 442); De Wildeman (1912b: 180); Thomas (1936: 73); Moldenke (1980: 219). Type:— CAMEROON. Yaunde, 1890/92, Zenker 319 (lectotype designated by Thomas (1936): B, not seen).

= Clerodendrum triplinerve var. grandiflorum Moldenke (1953a: 177) . Type :—D.R. CONGO. Ferme Pirard, à Kilubi, 980 m, mars 1946, Quarré 7768 (holotype: BR0000016596719!).

= Clerodendrum formicarum var. sulcatum Thomas (1936: 74) ; Robyns (1947:146).Type:— TANZANIA.Uluguru-Gebirge, (=? Morogoro), 1300 m, 9 January 1933, Schlieben 3217 (holotype: B†, iso-: BR0000008714879!; K000192879; LISC011435), nom inval.

Suffrutex with tufted annual shoots 0.2–1.3 m from a horizontal rootstock (in savannah and woodland), or sarmentose shrub or liana up to 6 m high and 1.5 cm diam. (in dense humid forest). Stem reddish with pale lenticels, puberulous, either solid and terete, or hollow and with 6–8 ridges; persistent petiole bases present or not, 2–5(–9) mm; rhytidome of old shoots (in lianose forms) greyish. Leaves 3 or 4-whorled; petiole 0.5–2.0(–3.5) cm, canaliculate, puberulous on angles; lamina obovate-elliptic to obovate-oblong, 3.5–11(–13) × 1.5–4.5(–6.5) cm, base rounded to cuneate, apex acuminate, 4 pairs of veins, the lowermost one often more conspicuous, glabrous or, occasionally somewhat puberulous on lower surface of main veins, upper surface shiny, lower surface gland-dotted, margin recurved, occasionally shortly ciliate in tip. Inflorescence umbelliform, 6–12(–20) cm diam. in the apex of the shoot, sessile or with peduncle up to 3 cm; rachis 1–7 cm long, with 4–7 nodes, each node with 3 branches almost perpendicular to rachis, bracts linear to filiform; branches up to 4–5.5 cm, puberulous, bearing small cyme.Flower: pedicel 2–8 mm; calyx tubular-campanulate, 2.5–3.5 mm long, lobes 1–1.5 mm long, triangular, puberulous, gland-dotted; corolla: tube 4–7 mm, glabrous, lobes 2–3(–5) mm long, puberulous and with sessile glands on the outer surface, whitish to greenish yellow, bad-smelling; stamens protruding 3–5(–8) mm, anther ca. 1 mm long. Fruit obovoid, 7–15 mm long, dark green to black, shiny, subtended by cup-shaped to flat persistent calyx 6–9 mm diam; seeds with orange aril.

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

Distribution elsewhere:— Angola, Cameroon, Central African Republic, Congo, Egypt, Equatorial Guinea, Gabon, Ghana, Guinea, Ivory Coast, Kenya, Liberia, Nigeria, Sudan, Tanzania, Uganda, Zambia.

Habitat:—Savannah, often on sandy soil, dry woodland, termite mound, dense forest; 500–1600 m.

Selection of representative specimens:—D.R. CONGO. Bas-Congo: Thysville [Mbanza Ngungu], 3 June 1915, Bequaert 7734 (BR!); Kisantu, November 1951, Callens 2905 (BR!); Kilenga, 25 October 1958, Pauwels 353 (BR!, WAG). Kasaï: Sangaie (territ. Lusambo), February 1939, Gillardin 507 (BR!); Kikwit, 21 November 1990, Masens 581 (BR!). Bas-Katanga: Basase, 13 October 1936, Matagne 226 (BR!); Haut-Lomami, Kaniama, 29 October 1947, Mullenders 1423 (BR!); Kiala (Manono), February 1954, Thiébaud 729 (BR!). Forestier Central: Eala, 16 March 1931, Corbisier-Baland 949 (BR!); Yangambi, 22 August 1959, Jeanty 151 (BR!); Djugu, Kibali, September 1931, Lebrun 3918 (BR!); Yangambi, plateau de la Lusambila, 1 May 1936, Louis 1792 (BR!). Ubangui-Uele: Région de Gwane, 8 July 1955, Boutique 158 (BR!); Tukpwo, 13 April 1954, Gérard 1228 (BR!). Lac Albert: Mboga, 18 March 1914, Bequaert 3012 (BR!); Réserve de Djugu, 29 October 1951, Smeyers 59 (BR!); Lekwa (Djugu), 10 July 1946, Taton 162 (BR!); Lacs Edouard et Kivu: Territ. Mwenga, Mudubwe, 21 May 1959, A. Léonard 4286 (BR!); Parc National Albert [Virunga], 24 July, 1954, de Witte 10761 (BR!); Mulungu, Kisharo, 8 June 1959, Pierlot 3059 (BR!). Haut-Katanga: Plateau de la Manika, env. Katentania, November 1912, Homblé 818 (BR!); Plateau de Muhila, Kansimba, 5 October 1986, Kisimba & Muzinga 17 (BR!); 8 km from Kolwezi, 17 August 1986, Schaijes 3042 (BR!).— RWANDA: Lacs Edouard et Kivu: Forêt de Nyungwe environs du Kamiranzovu, September 1971, Bouxin 1200 (BR!, WAG). Rwanda-Burundi: Nshiri (Kibungo), 28 June 1978, Troupin 16155 (BR!).— BURUNDI. Lacs Edouard et Kivu: Gihanga, 3 December 1958, Van der Ben 2369 (BR!). Rwanda-Burundi: Muremera, crête vers Kayangozi, 29 October 1966, Lewalle 1186 (BR!, MO); Kwitaba, 13 December 1977, Reekmans 6750 (BR!, L, LG). Lectotypification of Clerodendrum triplinerve Rolfe. The protologue cited three collections: Marques 50, Welwitsch 5622, Welwitsch 5661. However, the latter two were previously cited in the original materials of Clerodendrum formicarum G ü rke. Therefore, it is preferable to designate Marques 50 as the lectotype.

Note:— Clerodendrum formicarum is polymorphic for growth form, from suffrutescent with annual shoots in frequently burnt savannah (Bas-Congo, Kwango, Katanga), to lianose in rainforest (Forestier central, Ubangui-Uele, Lac Albert , Lacs Edouard et Kivu). It comprises forms with smooth, terete stems, and forms with 6- to 8-ridged thickened bark. The latter have been described as “ var. sulcatum ” by Thomas (1936: 74), an invalid name (no latin diagnosis). The presence of ridges is partly correlated with growth form, being more frequently observed in long-lived lianose shoots; however, ridges are also occasionally found in young shoots in suffruticose forms, including in the type of “ var. sulcatum ” (Schlieben 3217) and, vice versa, there exist lianescent specimens with terete shoots (e.g. Schmitz 8030). The taxonomic significance of this character needs further investigation. Selected specimens with ridged shoots in our territory:—D.R. CONGO. Kasaï: Région de Djamu , February 1921, Vanderyst 8913 (BR!). Forestier Central: Djugu, September 1931, Lebrun 3918 (BR!); Weko, route de Yambao, 23 March 1939, Louis 14050 (BR!). Ubangui-Uele: Région de Gwane, 8 July 1955, Boutique 158 (BR!). Lac Albert: Entre Mboga et Lesse, 18 March 1914, Bequaert 3012 (BR!); Lekwa (Djugu), 10 July 1946, Taton 162 (BR!). Lacs Edouard et Kivu: Parc de Kahuzi-Biega, 12 June 2010, Shalukoma 46 (BR!).— RWANDA. Rwanda-Burundi: Nshiri (Kibungo), 28 June 1978, Troupin 16155 (BR!).— BURUNDI. Lacs Edouard et Kivu: Bugarama, 25 May 1969, Lewalle 3867 (BR!). Rwanda-Burundi: Territ. Kitega, 20 km en aval de Karuzi, 15 July 1958, Van der Ben 2175 (BR!)).

Remaining syntypes of Clerodendrum formicarum .— ANGOLA. Golungo Alto, Queta mountains, Nov. 1854, Welwitsch 5622 (COI00005736, K000192934, LISU223608, LISU223609, P00442349); Golungo Alto, Queta mountains, July 1856, Welwitsch 5661 (COI00005737, K000192933, LISU223606, LISU223607, LISU223610, P00442350); Seengebiet, Bukoba, 21 November 1891, Stuhlmann 1026 (B†); Kampine, bei Malange, April 1877, Buchner 77 (B†); Malange, August 1879, Mechow 192 (JE00004300).—D.R. CONGO. Oberes Kongo Gebiet, Mussumba des Muata Jamwo, February 1876, Pogge 338 (B†). In addition, the protologue cites: Ghasal-Quellen Gebiet, bei Munsa, 8 April 1870, Schweinfurth 3483; however, this is probably a typo, because Schweinfurth 3483 (K000234220) is Tacazzea pedicellata K.Schum. (Asclepiadaceae) .

Remaining syntypes of Clerodendrum yaundense Gürke. — CAMEROON. 15 July 1891, Zenker 561 (B†); 14 October 1894, Zenker & Staudt 485 (B†); 27 March „1895“ (in protologue, 1896 on label), Zenker 813 (G00366320, K000192855, K000192856, P00442393 ).