Sabicea batesii Wernham (1914: 53)

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

3. Sabicea batesii Wernham (1914: 53) ( Fig. 9 ) Pseudosabicea batesii (Wernham) N. Hallé (1963: 170) . Lectotype (designated here):— CAMEROON. Bipindi (“Bipinde”), 1911, G. Zenker 4070 (lectotype BM! [barcode unknown];

isolectotypes BR, [ BR0000013213305 ]!, E [E00193649], G [G00014621], GOET [GOET010501], P [P00077583,

P00077582]!, S [S05-10060], WU [WU0033066]).

Sarmentose woody vine; stems 1–2.5 m long, 3–7 mm thick, ascending and arcuate, rooting at base, densely felted with buff woolly hairs, at length becoming glabrescent. Leaves solitary at each node, opposed to a stipule; petioles 0.7–3 (–4) cm long, densely felted all around and villose on the upper side with stiff hairs ca. 1.5 mm long; blades elliptic, (11.2–) 16.5–26 x (4.5–) 5.2–11.2 cm, asymmetrical at base with proximal side subcordate to rounded, and distal side obtuse and inserted 2–10 mm higher, acuminate at apex, coriaceous and strongly discolorous; upper side green, villose on the midrib and sometimes sparsely so on the lamina, with stiff hairs 1–2 mm long; lower side buff (purplish when young), densely felted with woolly hairs; 10–18 secondary veins on each side of midrib. Stipules solitary (i.e. one per node), leaf-opposed, those of flowering nodes often splitting, shortly connate to the petiole, ovate, (9–) 12–20 x (3–) 7–12 mm, divided in 2–3 short segments 1–4(–8) mm long, densely felted with buff woolly hairs outside, villose inside with 2–3 mm long silky hairs forming a triangular area near the base. Inflorescences on leafy portion of stems, opposed to the leaf of the same node, initially arising by piercing the base of the stipule which later splits or falls as the inflorescence develops, 1(–2) per node, sessile, glomerulate, 1–3 cm in diameter. Bracts buff, +/- enclosing the flowers when young, broadly ovate, concave, entire, acute to obtuse at apex, 6–7.5 x 3–6 mm, densely felted outside with additional long silky hairs 1.5–3 mm at base, glabrous inside except for long silky hairs at base; bracteoles narrowly ovate to narrowly triangular, minutely toothed, 4–5 x 1–2.5 mm, with same indumentum as the bracts. Flower buds enlarged at apex. Flowers 5(–6)-merous, sessile, heterostylous. Hypanthium with long silky and short woolly hairs intermingled. Calyx buff outside and pale green inside; tube 2–2.5 mm long, densely felted outside, glabrous inside; lobes narrowly elliptic to narrowly triangular,

TAXONOMIC REVISION OF SABICEA SUBGENUS ANISOPHYLLAE

Phytotaxa 293 (1) © 2017 Magnolia Press • 21 1.7–2.5 x 1–1.6 mm, densely felted outside and sometimes villose on the margin, sparsely villose with short appressed hairs inside; one tiny colleter between each pair of calyx lobes. Corolla entirely white; tube nearly cylindrical, ca. 4.5 x 2 mm; lobes triangular, 2–3 x 1.2–1.8 mm; outside of corolla glabrous on tube, hairy on lobes with dense felt of woolly hairs intermingled with stiff hairs ca. 1 mm long; mouth and base of lobes inside densely bearded with white multicellular hairs ca. 1 mm long; inside of tube villose in upper half in long-styled flowers, or only near the throat and with a separate ring of hairs around the middle in short-styled flowers. Stamens included, subsessile, attached at about the upper 1/3 rd of the tube in long-styled flowers, exserted, with filaments exceeding corolla mouth by ca. 1 mm in short-styled flowers; anthers 1.2 x 0.4 mm long. Disk cylindrical, ca. 0.3 mm long, glabrous. Style glabrous, ca. 6 mm long, exserted in long-styled flowers, ca. 3.5 mm long, included in short-styled flowers; stigmatic lobes 1–1.2 mm long, broadly elliptic, +/- flattened. Fruits greenish-white to pale brown, ellipsoid or obovoid, 5–7 x 4–6.5 mm when dry, sessile, usually with long silky and short woolly hairs intermingled, rarely with short woolly hairs only. Seeds pale brown, polygonal, ca. 0.6 x 0.3 mm, the surface with dense faint parallel striations.

Distribution: —Lower Guinea Domain. The species occurs in Cameroon where it is apparently very local, Equatorial Guinea, and Gabon where it is widespread and locally abundant in the west and centre of the country ( Fig. 10 ).

Habitat and ecology: —Forest edges in half-shade, especially along roads and streams (which are probably the original habitat); at 30–1000 m altitude. The species is particularly abundant in high rainfall areas (Cristal and Chaillu Mts in Gabon) where it is locally dominant in roadside vegetation, forming dense thickets.

Phenology: —Flowering probably throughout the year, recorded in all months except July and September; fruits in March, May and November–January.

Discussion: — Wernham (1914) described S. batesii citing two syntypes, Zenker 4070 and Bates 536. The former is better distributed in herbaria, and the specimen of this collection deposited at BM, where Wernham worked, is chosen as the lectotype.

Sabicea batesii is unique in the genus in having the inflorescences growing through the stipules, arising through a hole at their base; however, this character can only be seen on young inflorescences, since they later break up the stipule while expanding. The species is further unusual in the genus in having pseudo-alternate leaves

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ZEMAGHO ET AL.

opposed to a stipule of the same node, a character shared with S. sthenula , S. mapiana , and some variants of S. mildbraedii var. glabrescens . The differences between these four species are summarised in Table 4; the latter two species are especially similar to S. batesii , but are less robust plants and have the inflorescences borne inside the stipules. Sabicea batesii also resembles in habit other tall sarmentose species ( S. aurifodinae , S. crystallina , S. jacfelicis , S. ndjoleensis and S. sciaphilantha ) but all these species have the leaves in unequal pairs, and inflorescences mostly borne on older stems below the leafy nodes; with the exception of S. jacfelicis , they also have much longer corollas than those of S. batesii . The stipules of S. batesii , described as entire by Wernham (1914), are in fact 2- to 3-fid, usually shortly so. However, damaged or old stipules can appear entire at the apex.

The collection N. Hallé & G. Cours 5945, without flowers or fruits, was cited with doubt by Hallé (1966: 204) under Sabicea batesii in the Flore du Gabon and later considered by Hallé (1971: 317) as probably belonging to Pseudosabicea aurifodinae var. crystallina . This specimen is too pubescent for being either S. batesii or S. crystallina , and also differs from the former in having the leaves in unequal pairs; therefore, we refer it to S. sciaphilantha subsp. hirsuta .

A collection from Equatorial Guinea, Lisowski M-1400 (BRLU), resembles S. batesii in having pseudoalternate leaves and inflorescences borne outside the stipules, but has smaller leaves and more pubescent calyx lobes. This specimen lacks good flowers and better material from the same area is needed to decide its status; it could possibly be a hybrid between S. batesii and S. parmentierae .

Conservation status:— IUCN Red List Category: Least Concern [LC]. The extent of occurrence is estimated as 136,651.117 km 2 and the area of occupancy as 124.000 km 2 based on herbarium records. The latter feature falls

TAXONOMIC REVISION OF SABICEA SUBGENUS ANISOPHYLLAE

Phytotaxa 293 (1) © 2017 Magnolia Press • 23 within the limit for Endangered under criterion B2, but is obviously much underestimated, since we observed the species to be common and widespread along many roads in the central part of Gabon. The species is known from more than 10 locations (sensu IUCN 2012), occurs mostly in sparsely populated areas, and is actually favoured by small-scale forest clearance due to its preference for open and disturbed habitats; it is therefore not threatened.

Additional specimens examined:— CAMEROON. Bakossi Mountains 1–8 km NNE of Menyum Village, 22–30 May 1987, C. Doumenge 597 ( BR, MO, WAG) ; Mokoko Forest Reserve , Ekombe–Mofako, 3 June 1994, D. Pouakouyou & M. Etuge 33 ( MO) ; près Mokoko River Forest Reserve , 40 km NW de Muyuka, 31 May 1976, B. Satabié 290 ( BR, P) ; Mokoko Forest Reserve , 1 May 1995, B. Sonké 1079 ( BR) ; Bakossi forest between Nyandong and Molongo, 18 February 1987, D.W. Thomas 6695 ( MO, WAG, YA) ; road 5 km N of Mekalat (to Lolodorf ), 11 March 1997, B. S. van Gemerden 80 ( SCA, WAG, YA) . EQUATORIAL GUINEA. Rio Mbambala , campement Shimmer km 16 (entre Rio Muni et Monte Mitra), 22 August 1997, N. Nguema & J. Lejoly 13 ( BRLU, P) ; inselberg de Bicurga, près du village de Bicurga , 24 May 2002, I. Parmentier & P. Esono 3398 ( BRLU) ; SO du Parc National de Monte Alén, entre la station Ecofac de Mosumo et Monte Boracho, 12 February 2001, B. Senterre & D. Ngomo 2791 ( BRLU) ; 4 km N de Mitong , 12 December 2003, B. Sonké & P. Esono 3143 ( BR, BRLU, MO) . GABON. Mfoa , 85 mi. E of Gabon, October 1896, G.L. Bates 536 (BM, G, K, P) ; 8 km SSW of the hydroelectric power station in the Mbé River at Kinguélé, 28 August 1978, F.J. Breteler & J.J.F.E. de Wilde 352 ( BR, P, MO, WAG) ; Crystal Mountains , 3 km NE of Kinguélé, road from Kinguélé to Tchimbélé, 11 September 1994, F.J. Breteler 12809 ( WAG) ; Barrage de Kinguélé , downstream of the hydroelectric power station, 19 November 1986, J.J.F.E. de Wilde, J.C. Arends, J. & de Bruijn 8834 ( BR, MO, P, WAG) ; Monts de Cristal , inselberg Milobo, 10 km N Mbé Akélayong, 50 km W Medouneu, 3 December 2001, J. Degreef 245 ( BR) ; km 6 Tchimbélé – Kinguélé , 7 February 2008, S. Dessein, O. Lachenaud, S. Janssens, Y. Issembe & T. Nzabi 1746 ( BR, LBV, WAG) ; Doudou Mountains National Park , ca. 8 km S of Peny, 16 February 2008, S. Dessein, O. Lachenaud, S. Janssens, Y. Issembe & T. Nzabi 1911 ( BR) ; Mouyanama falls , at base of Mt Songou, 22 February 2008, S. Dessein, O. Lachenaud, S. Janssens, Y. Issembe & T. Nzabi 2076 ( BR) ; Boussimbi village , at base of Mt Iboundji, 4 Mars 2008, S. Dessein, O. Lachenaud, S. Janssens, Y. Issembe & T. Nzabi 2376 ( BR) ; km 18 à l’E de Libreville , 28 January 1961, N. Hallé 930 (P) ; km 18 de Libreville , 2 April 1963, N. Hallé 1528 (P) ; Abanga , chantier CEFA, 1 June 1963, N. Hallé 2125 ( BR, P) ; chutes de Kinguélé , rivière Mbei, 15 January 1968, N. Hallé & J.F. Villiers 4440 (P) ; Mont Mvélakéné , 6 km SW Méla, 14 February 1968, N. Hallé & J.F. Villiers 5258 (P) ; Moumba côté ouest, environs d’Etéké, 19 May 1963, N. Hallé & G. Cours 6049 (P) ; Moubigou 2, 21 May 1963, N. Hallé & G. Cours 6140 (P) ; Piste du Lac Azingo , ca. 10 km au NE du lac et 30 km au NW de Lambaréné, 26 October 2014, O. Lachenaud, D. Ikabanga, E. Bidault, B. Lissambou & I. Lafferty 2081 ( BR, BRLU, LBV, MO, WAG) ; Monts de Crystal , Kinguélé, 13 April 2006, M.E. Leal, D. Nguema, E. Mounoumoulossi & P. Bissiemou 1100 ( BR) ; Waka National Park . ca. 10 km SE of Oghoubi Camp, 20 March 2007, M.S.M. Sosef, J.J. Wieringa, B. Nziengui, P. Bissiengou, & J. Boussiengui Nongo 2455 ( WAG) ; Concession Bordamur , SE of Ndjolé, 26 February 2009, T. Stévart, G. Dauby, D. Nguema, E. Mounoumoulossi & P. Bissiemou 3074 ( BR) ; Doudou Mountains , Igotchi, 21 November 2003, J.L. C. H. van Valkenburg, C.C.H. Jongkind, R. Niangadouma & A.J. Mabicka 2569 ( BR, MO, WAG) ; Crystal mountains , 1½ km SW of Tchimbélé, along side of an old road, 22 December 1989, J.J. Wieringa 275 ( BR, MO, WAG) ; Crystal Mountains , 14 km on the road from Kinguélé to Tchimbélé (=57 on SEEG road), 13 November 2004, J.J. Wieringa ,, C.M. Wilks, T. Nzabi & A.C. Ley 5410 ( MO, WAG) ; Crystal Mountains N.P., 9 km on road from Kinguélé to Tchimbélé, 26 March 2013, J.J. Wieringa, A.S.J. van Proosdij & T. Nzabi 7766 ( WAG) .

Figures

FIGURE 9. Sabicea batesii. 1, portion of stem with one leaf and stipules; 2, flowering stem; 3, bract; 4, section of short-styled flower; 5, disk. Sabicea aurifodinae; 6, portion of stem with two unequal leaves and stipules; 7, flowering stem; 8, bract seen from inside; 9, section of short-styled flower; 10, anthers, seen from front (left) and back (right); 11, disk; 12, cross section of ovary. From N. Hallé 2125 (1–5) & N. Hallé 6137 (6–12). Drawing by N. Hallé, reprinted with permission from Hallé (1966: 203).

FIGURE 10. Distribution of Sabicea batesii and S. bequaertii.