Sabicea parmentierae Zemagho, O. Lachenaud & Sonké, 2017

Zemagho, Lise A., Liede-Schumann, Sigrid, Lachenaud, Olivier, Dessein, Steven & Sonke, Bonaventure, 2017, Taxonomic revision of Sabicea subgenus Anisophyllae (Ixoroideae, Rubiaceae) from Tropical Africa, with four new species, Phytotaxa 293 (1), pp. 448-450 : 448-450

12. Sabicea parmentierae Zemagho, O. Lachenaud & Sonké , sp. nov. ( Fig. 27 )

Type :— CAMEROON. Bidjap, 32 km E Nyabesan, 7 March 1963, J. Raynal & A. Raynal 10282 (holotype P!; isotype YA!) .

Sabicea parmentierae resembles S. medusula , S. sthenula and S. mildbraedii in general habit. It is best separated from these by the characteristic calyx lobes, with a narrow erect base bearing dense stiff hairs inside, and an enlarged apex bending outwards and much less pubescent; whereas, in the other species the calyx lobes are linear to triangular, with hairs evenly distributed on the inside. It also differs from S. mildbraedii in the calyx lobes 3.5–4.5 mm long (vs. 1–3.5 mm long) and the corolla with a red to pink tube 6.7–7 mm long and white lobes (vs. entirely white, with tube 3.5–4.5 mm long); and differs from S. medusula and S. sthenula in the flower buds with a strongly enlarged apex (vs. nearly cylindrical), the short-styled flowers with exserted stamens (vs. included), and the stipules with linear lobes (vs. entire or with relatively broad triangular lobes); and from all the above cited species in the corolla lobes 3–5 mm long (vs. 1.5–3 mm long), and the bracts entirely villose inside (vs. glabrous except at base).

Small, creeping rhizomatous herb 10–20 cm tall; stems 1–2 mm thick, main stems creeping, lateral flowering stems ascending and arcuate; persistently villose, with stiff patent purplish hairs ca. 3 mm long, and sparsely white-felted when young. Leaves opposite, strongly unequal, one of them much smaller; smaller leaves with petioles 0.1–0.3 cm long and blades 0.4–0.8 x 0.2–0.4 cm; normal-sized leaves with petioles 0.5–3.8 cm long, with same indumentum as the stems; blades elliptic to slightly obovate, 3.4–15.3 x 1.5–6.4 cm, strongly asymmetrical at base with proximal side rounded to subcordate and distal side acute to subcordate inserted 2–7 mm higher, gradually acuminate at apex, papery, strongly discolorous; upper side green, sparsely to densely villose with stiff hairs ca. 1 mm long, and shorter uncinate hairs also present on the veins; lower side white or pinkish-buff, densely felted with woolly hairs, and villose on the veins (sometimes sparsely so on the lamina as well) with stiff hairs 1–1.5 mm long; secondary veins 7–12 on each side of midrib. Stipules opposite, interpetiolar, connate at base with the reduced leaf and very shortly with the petiole of the normal leaf, erect to patent, 4–16 x 1.5–4 mm, deeply divided (for ½ to ¾ of their length) into 3–7 linear segments 2–9 mm long, sparsely villose outside with stiff hairs 1–1.5 mm long (sometimes restricted to the margin) and sparse woolly hairs sometimes present as well, glabrous inside except the base with stiff hairs ca. 3 mm long. Inflorescences axillary on leafy portion of stems, one per node, sessile, densely glomerulate, many-flowered, 0.9–1.8 cm in diameter. Bracts and bracteoles ± hidden between the flowers, not enclosing them; bracts elliptic, ca. 4 x 1.5 mm, entire or shortly dentate, acute at apex,villose on both sides, with stiff hairs ca. 1 mm long; bracteoles narrowly elliptic to linear, 2–7 x 0.2–1.5 mm, with same indumentum as the bracts. Flower buds with apex broader than long, much wider than the tube. Flowers 5-merous, sessile. Hypanthium densely hirsute. Calyx white outside, green with purple hairs inside; tube ca. 1.5 mm long, villose with long stiff hairs outside, glabrous inside; lobes spathulate, sometimes narrowly so, 3.5–4.5 x (0.5–) 1–1.5 mm, the apex acute or obtuse and conspicuously bending outwards, outside densely white-felted and sparsely villose with stiff hairs 0.7–2 mm long, inside with long stiff hairs very dense on the narrow basal part and sparse or absent on the enlarged upper part. Corolla with red to pinkish tube and white lobes; tube 6.5–7 x 1–1.5 mm, narrowly infundibuliform, ± widening near the apex; lobes triangular, 3–5 x 1.5–4 mm; corolla tube glabrous outside, lobes densely villose outside, with stiff hairs 0.7–2 mm long intermingled with short woolly hairs; mouth and base of lobes inside densely bearded with white moniliform hairs 1.5–2 mm long; tube inside either villose at distal 2 mm down to the base of anthers inside in long-styled flowers, or villose at distal 1 mm and with 5 patches of short hairs ca. 2.5 mm below the mouth (short-styled flowers). Stamens included, subsessile, attached ca. 2 mm below mouth in long-styled flowers, exserted and +/- hidden between the hairs of the corolla mouth, with filaments ca. 1.5 mm long inserted 2.5 mm below mouth in short-styled flowers; anthers 1.5–2 x 0.4 mm long. Disk cylindrical, ca. 0.3 mm long, glabrous. Style glabrous, 8.5 mm long, exserted, ± hidden between the long hairs of the corolla-mouth in long-styled flowers, 6 mm long, included in short-styled flowers; stigmatic lobes ca. 1.5 mm long, broadly elliptic and +/- flat. Fruits green to white (mature?), ellipsoid, 5–6 x 4.5–5 mm when dry, densely villose with long hairs ca. 2 mm long, subsessile. Seeds brown, polygonal, ca. 0.4 x 0.3 mm, the surface with dense parallel striations.

54 • Phytotaxa 293 (1) © 2017 Magnolia Press

ZEMAGHO ET AL. TAXONOMIC REVISION OF SABICEA SUBGENUS ANISOPHYLLAE

Phytotaxa 293 (1) © 2017 Magnolia Press • 55

Etymology:— The species is named after Dr Ingrid Parmentier, formerly of the University of Brussels, specialist of the inselberg flora and one of its collectors.

Distribution: —Lower Guinea Domain. S. parmentierae occurs in the extreme south of Cameroon, Equatorial Guinea, and northern Gabon ( Fig. 26 ).

Habitat and ecology: —Half-shaded places in forest, usually along streams, in low thickets on inselbergs, or along forest tracks; at 490–1110 m altitude.

Phenology: —Flowering in February–May and August–November; fruiting in January, March, May and October.

Discussion: — Sabicea parmentierae resembles S. medusula , S. sthenula , and S. mildbraedii in general habit; the morphological differences are discussed in the diagnosis and are presented in Table 5. The species range is allopatric with respect to that of S. mildbraedii , although it partly overlaps with those of S. medusula and S. sthenula .

One of the first collections of S. parmentierae, N. Hallé & Villiers 5048 from Gabon, was referred to S. medusula by Hallé (1971). So far, we have not seen any specimen of S. medusula from Gabon, although the species is expected to occur there.

Although this species is well characterised, some collections showing intermediate characters with S. medusula and S. batesii have been noted; they are discussed under these two species.

Conservation status:—IUCN Red List Category: Near-Threatened [NT]. The extent of occurrence is estimated as 35,305.138 km 2 and the area of occupancy as 56 km 2; the latter value falls within the limit for Endangered under criterion B2. The species is known from 14 subpopulations representing 13 locations (sensu IUCN 2012), which is above the limit for Vulnerable under the condition B2a. It occurs in two protected areas, Monte Alén National Park and the Monumento Natural de Piedra Bere, both in Equatorial Guinea. In view of its small range, and preference for inselbergs which are a vulnerable habitat, the species can be classified as near-threatened.

Additional specimens examined (Paratypes):— CAMEROON. South Province : Rocher d’Akoakas (± 35 km SE d’Ebolowa), 6 May 2009, O. Lachenaud, B. Lemaire, M. Simo & B. Sonké 600 ( BR) ; Colline Nkondo près Enyantoum , 20 km SW d’Ambam, 19 March 1970, R. Letouzey 10177 ( BR, P, WAG); Akoakas, 27 km SE Ebolowa, 15 February 1963, J. Raynal & A. Raynal 9732 (P) . EQUATORIAL GUINEA. Bata – Mongo (Alosa): estrada kms 77–78, 27 April 1995, M.F. de Carvalho 5518 ( WAG) ; Parc National de Monte Alén , transect de Monte Chocolate, 10 October 1994, J. Lejoly 94/216 ( BRLU) ; Région d’Anisok au dessus du village Nzuamayong, Inselberg Akuom, 11 September 1997, S. Lisowski M-678 ( BRLU) ; Région d’Anisok au dessus du village Nzuamayong, 11 September 1997, S. Lisowski M-705 ( BRLU) ; Région d’Anisok , environs de Temelon, près du village Ayene, 10 September 1997, S. Lisowski M-761 ( BRLU) ; Montagne près de Bikurga, 23 September 1997, S. Lisowski M-1389, M-1465, M-1467 & M-1472 (all BRLU) ; Entre Nsuameyong et inselberg Akuom, 16 January 1998, C. Obama & J. Lejoly 447 ( BRLU) ; Parc National de Monte Alén , dalle rocheuse d’Engong, 5 km à l’ouest du village d’Engong, 2 July 1999, I. Parmentier & P. Nguema 107 ( BRLU) ; Parc National de Monte Alén , dalle rocheuse de Monte Alén, 15 May 2002, I. Parmentier & P. Esono 3082 ( BRLU) ; inselberg de Bicurga, 24 May 2002, I Parmentier & P. Esono 3148 ( BRLU) ; Monte Alén , 9 August 2001, B. Sonké, P. Esono & S. Ndong 2482 ( BR, BRLU) . GABON. Akoga , 8 February 1968, N. Hallé & J.F. Villiers 5048 (P); Mintome, 31 March 2003, R. Mboma, J. Lejoly, A. Boupoya & B. Sonké 98 ( WAG) ; Rougier Logging Concession , Haut Abanga, east of Ndjolé, 18 February 2012, T. Stévart, V. Droissart, A. Boupoya, E. Akouangou, C. Nyangala & J.- N. Boussiengui 4309 ( LBV) ; besides access road to hydroelectric facility at Tchimbélé , 17 November 2002, J.S. Strijk 364 ( WAG) .

Figures

FIGURE 26. Distribution of Sabicea ndjoleensis and S. parmentierae.

FIGURE 27. Sabicea parmentierae. A, flowering stem; B, node with inflorescence, stipules and reduced leaf; C, portion of midrib and lateral nerve below with detail of indumentum; D, detail of a calyx lobe, outside; E, detail of a calyx lobe, inside; F, flower bud; G, long-styled flower; H, section of long-styled flower (calyx and ovary removed); I, section of short-styled flower; J, detail of a hair from the corolla mouth; K, detail of a hair from the outside of a corolla lobe; L, fruit. From N.Hallé & Villiers 5048 (A, F–G), Letouzey 10177 (B–C, J–K), Lejoly 94/216 (D–E, L), J. & A. Raynal 10282 (H–I). Drawing by Antonio Fernandez.