Clerodendrum capitatum var. capitatum

Meerts, Pierre, 2023, The genus Clerodendrum (Lamiaceae) in the flora of Central Africa (D. R. Congo, Rwanda, Burundi), Phytotaxa 594 (1), pp. 1-42 : 9-10

6a. Clerodendrum capitatum var. capitatum

= Clerodendrum conglobatum Baker (1900: 296) . Type: — ANGOLA. Pungo Andongo, prope Cabondo, January 1857, Welwitsch 5629 (lectotype designated here: BM000798624; isolecto-: BM000798625, G00366315, K000192923, P00442337) ≡ Clerodendrum capitatum var. conglobatum (Baker) Thomas ( Thomas 1936: 65) ; Moldenke (1985f: 436).

= Clerodendrum capitatum var. subcordatum De Wildeman (1903: 117 ; 1921: 166); Durand & Durand (1909: 438). Type: — D.R. CONGO. Haut-Katanga, March 1909, Lukafu, Verdick 422 (holotype: BR0000016591882!).

= Clerodendrum talbotii Wernham in Rendle et al. (1913: 91). Type: — NIGERIA. Oban, 1911, Talbot 341 (holotype: K000192839; iso-: BM000798622, K000192838) ≡ Clerodendrum capitatum var. talbotii (Wernham) Thomas ( Thomas 1936: 65) ; Robyns (1947: 143); Moldenke (1985f: 440).

Sarmentose shrub or liana, up to 6 m. Stem terete, with a mixed indumentum of very short appressed hairs and long patent hairs (ca. 4 mm long); persistent petiole base 3–10 mm, straight to slightly curved. Leaf: petiole 0.7–3.5(– 6.0) cm, of unequal length at a node, canaliculate, with patent hairs on upper side or glabrous; lamina obovate to elliptic, 7–17(–20) × 3–10.5 cm, base obtuse, rounded to subcordate, apex acuminate, margin entire, or, rarely distally undulate-crenate, upper surface pubescent to subglabrous, lower surface pubescent on veins, or subglabrous, 4–5 veins on either side, somewhat impressed on upper surface, reticulum slightly prominent above. Inflorescence on tip of shoot or on short lateral twigs, shortly pedunculate to subsessile, subtended by small leaves, capitate (2.0–) 2.5–4 cm diam.; floral bracts narrowly ovate-elliptic, similar to sepals, glabrous or sparsely pubescent, ciliate (cilia ≥ 0.5 mm). Flower: pedicel ca. 3 mm, generally glabrous; calyx: 11–20 mm long, tube 3 mm, glabrous, lobes ovate 8–16 × 5–9 mm, acuminate into a fine point, whitish green, often purple tinged, surface glabrous except for a few hairs on main veins, margin ciliate at least in tip, cilia (0.5–) 1–3 mm, often purplish, reticulum prominent; corolla: tube 50–90 mm, pubescent (glandular hairs), lobes 7–15 mm long, hairy (glandular hairs); stamens exceeding tube by 20–30(–40) mm, anther 2 mm long. Fruit: 4-lobed, ca. 10 mm long.

Distribution in Central Africa:—D.R. Congo, Burundi, Rwanda? (see note).

Distribution elsewhere:—Widespread in sub-Saharan Africa.

Habitat:—Dense rainforest of various kinds, secondary forest, riparian forest, rock outcrops.

Selection of representative specimens:—D.R. CONGO. Côtier: Ile Mateba, 10 May 1959, Wagemans 2337 (BR!). Bas-Congo: Fu (Plateau Bateke), 26 May 1982, Breyne 4364 (BR!); Kimbuba, June 1954, Callens 4574 (BR!).

Kasaï: Tumba (Territoire Luisa), 19 February 1957, Liben 2520 (BR!, P); Kapanga, s.d., Overlaet 147 (BR!). Bas Katanga: Gandajika, 22 March 1957, Liben 2788 (BR!); Haut Lomami, Kaniama, August 1947, Mullenders 239 (BR!); Gandajika, 15 May 1957, Risopoulos 576 (BR!). Forestier Central: Bas-Uele, 12 October 1934, De Wulf 160 (BR!); Zone de Mambasa (Ituri Forest), Epulu, 22 November 1996, Ewango 698 (BR!, WAG); Yangambi, réserve de flore d’Isalowe, 13 September 1937, Louis 6022 (BR!); Parc National Albert [Virunga], Bukotsa, 23 September 1954, de Witte 11126 (BR!, WAG). Ubangui-Uele: Kurukwata (Aba), 7 September 1957, Gérard 3678 (BR!, WAG); Monga, February 1931, Lebrun 2258 (BR!); Garamba, zone frontière du Soudan, 15 August 1952, Troupin 1934 (BR!, WAG). Lac Albert: Bassin du Shari, 17 October 1951, Smeyers 11 (BR!). Lacs Edouard et Kivu: Kamatumbe, 14 March 1934, de Witte 1532 (BR!); Katibombo, riv. Lusilube, 14 September 1955, Vanschuytbroeck in de Witte 12695 (BR!, WAG); Bendera , barrage de la Kiyimbi, September 1959, Schmitz 6490 (BR!). Haut-Katanga : Lukafu , March 1900, Verdick 422 (BR!).— BURUNDI. Rwanda-Burundi : Bururi, Kigwene , 23 November 1969, Lewalle 4091 (BR!).

Lectotypification of C. conglobatum Baker. Baker (1900) cited Welwitsch 5629 as the type; this collection is represented by at least 5 specimens in four herbaria; however, since Baker described the species long after the splitting of Welwitsch’s collection, he most likely worked on the materials kept in the United Kingdom. The specimen BM000798624 is the most complete one, displaying dissected floral materials, most likely studied by Baker ; it is chosen as the lectotype. The protologue mentions ca. 8 mm (“1/ 3 inch ”) for calyx length, out of the range of C. capitatum , certainly a typo; in all the original materials, calyx length is 12–16 mm. The remaining materials is best considered as consisting of syntypes, as pointed out by Albuquerque et al. (2009) ( BM000798625 , G00366315, K000192923, P00442337 ).

2. C. capitatum is variable for twig and leaf pubescence, leaf size and shape, length and number of calyx lobe cilia, pubescence of corolla tube, length of corolla lobes and stamens; however, those traits are poorly correlated and most of the infraspecific taxa that have been described appear to be of low taxonomic value. In D.R. Congo, however, two varieties deserves taxonomic recognition ( var. vanderystii and var. pubitubum )

3. Three specimens, all from the same region in the north of D.R. Congo (De Graer 708, Gérard 1854, Gérard 4652) have unusually small calyx (6–9 mm long), with reticulum not prominent, and few-flowered inflorescence (<12 flowers); they could represent a distinct taxon, but more materials (especially corollas) are needed.

4. C. capitatum is recorded by the Flore du Rwanda ( Malaise, 1985), based on Raynal 20764. However, we have not seen that specimen.

5. Records of Clerodendrum cephalanthum in our territory are erroneous, based on specimens of C. capitatum with calyx cilia sparser and shorter than usual.