Barleria lobelioides Champl., 2011

Dominique Champluvier, 2011, New and overlooked Acanthaceae taxa from D. R. Congo, Rwanda and Burundi: (1) the genus Barleria, Plant Ecology and Evolution 144 (1), pp. 82-95 : 89

Barleria lobelioides Champl. , sp. nov.

Ab omnibus speciebus Barleriae propter calycis lobos maximos acuminatos-cuspidatos et integros differt; propter flores in capitulis crassis terminalibus vel axillaribus dispositas foliisque numerosis subtentas proprius est; B. macrostegiae similis sed propter calycis lobos multo angustiores; propter bracteas, calycis lobos foliaque majores non coriaceos dense pilososque et propter distributionem valde differt.

– Type: D.R.Congo, District du Haut-Katanga, Fungurume, alt. 1300 m, May 1985, Malaisse & Goetghebeur 515, fl (holo-: BR; iso-: B, C, CAS, K, LISC, MO, P, UPS, WAG).

Prickless suffrutescent more or less prostrate plant. Stems densely covered with long spreading hairs. Lamina of the leaves ovate to ovate-elliptic, cuneate to subrounded at the base, acute at the tip, 2.5–4.8(–7.5) × 1.2–2.5 cm, covererd with long thin more or less adpressed hairs; nerves somewhat depressed above, prominent below; leaves subsessile or petiole up to 5 mm long. Inflorescences capitate or in dense short (more rarely rather long) spikes, terminal or on short lateral shoots and subtended by leaves; bracts, bracteoles and calyx covered with long fine adpressed hairs and with shorter rather flexuous hairs and glandular hairs; bracts elliptic, 2.5–3.7 × 1.2–1.8 cm, acuminate; bracteoles narrowly elliptic, rather asymetric, cuspidate, 3.3–4 × 0.4–0.7 cm; calyx with posticous lobe narrowly elliptic, cuspidate, 3–3.6 × 0.8–1 cm, anticous lobe 2.9–3.5 × 0.8–1.3 cm, similar to the posticous one but bifid on 5–15 mm long, with the two teeth cuspidate; corolla white, 3.5–5 cm long, tube 2.3–3 cm long, 6–10 mm wide at the throat, slightly pubescent and glandular outside; lobes elliptic to suborbicular, upper lobes 12–16 × 6–9 mm, median lower lobe 13–22 × 10–15 mm, lateral lower lobes 12–15 × 6–14 mm; fertile stamens 2, with filament 16 mm long and black anther 3–4 mm long, included in the tube; staminodes 2–3, included, with filament 2–7 mm long and reduced anther; style 25–32 mm long, stigma capitate. Capsule (submature) ellipsoid, blackish, glabrous, 20 × 7 mm. Fig. 7 .

Distribution – Species of the Zambezian centre of endemism. Endemic from Katanga, strictly bound to metalliferous deposits. Fig. 8 .

Other collections examined – D.R.Congo. District du Haut-Katanga: Tenke, May 1957, Duvigneaud 3023 A, fl (BRLU); Kwatebala, May 1980, Malaisse 10906, fl (BR); Fungurume,1956, Duvigneaud 2250 B, fr (BRLU); ibid., May 1957, Duvigneaud 3019Ac, fl (BRLU); ibid., May 1957, Duvigneaud 3023A, fl (BRLU); ibid., Jun. 1957, Duvigneaud 3446Ac, fl (BRLU); ibid., alt. 1230 m, Jun. 1997, Malaisse, Kisimba & Muzinga 9, fl (BR); Tilwizembe, May 1957, Duvigneaud 3081Ac, fl, fr (BRLU); ibid., May 1957, Duvigneaud 3138A, fl, fr (BRLU); Mambilima, alt. 1300 m, Jun. 1997, Malaisse, Kisimba & Muzinga 19, fl (BR); Kwatebala, alt. 1500 m, Jun. 1997, Malaisse, Kisimba & Muzinga 50, fl (BR); Kabwelunono, alt. 1475 m, Jun. 1997, Malaisse, Kisimba & Muzinga 139, fl (BR); Fungurume, alt. 1170 m, Apr. 1974, Malaisse 7732, fl (BR); ibid., alt. 1200 m, Apr. 1980, Malaisse 10524, fl (BR); ibid., alt. 1200 m, Feb. 1978, Malaisse & Grégoire 123 (BR); ibid., alt. 1170 m, Apr. 1990, Tropmetex 148, fl (BR); Tilwizembe, alt. 1300 m, Apr. 1990, Tropmetex 242, fl (BR).

Habitat – Steppes and savannas, Uapaca robynsii bushy savannas; on cobalt and copper deposits only, 1170–1500 m.

B. lobelioides has the same kind of habit and inflorescence as B. macrostegia, a species confined to Namibia, Zimbabwe, Botswana and South Africa. B. macrostegia is less robust, having coriaceous, glabrous leaves, much broader, widely elliptic coriaceous calyx lobes and a smaller corolla with an almost cylindrical tube. The leaves and calyx lobes of B. lobelioides are not coriaceous and are villous, the calyx lobes being narrowly elliptic, and the corolla is larger with an infundibuliform tube. After Balkwill & Balkwill (1997), B. macrostegia belongs to sect. Barleria . That section is characterized, inter alia, by the strongly different shape and size of the outer and inner calyx lobes; it is not the case in B. lobelioides, but all the other characters match these of that section and, in our opinion, B. lobelioides can be considered as a peripheral member of the latter. It is remarkable to notice that almost all the specimens have been collected since 1980 only.

Figures

Figure 7 – Barleria lobelioides. A, habit; B, bract; C, posticous calyx lobe; D, anticous calyx lobe; E, lateral calyx lobe; F, opened corolla; G, pistil (A, Brooks et al. 148; B–G, Duvigneaud 3023 A).

Figure 8 – Distribution map of Barleria lobelioides and Barleria cinnabarina.