Sabicea floribunda var. paucinervis Wernham,

Lachenaud, Olivier, Zemagho, Lise & Sonké, Bonaventure, 2020, A synopsis of the Sabicea floribunda group (Rubiaceae) from Central Africa, including three new species, Candollea 75 (1), pp. 115-143 : 130-132

3d. Sabicea floribunda var. paucinervis Wernham, Monogr. Sabicea: 73. 1914 ( Fig. 7B ).

Lectotypus (designated here): CAMEROON. Reg. South: Gross-Batanga, 3.XII.1890, imm.fr., Dinklage 743 ( P [ P 03793520]!; isolectotype: WAG [ WAG 0034480]!). Syntypus: CAMEROON. Reg. South: Kribi, 24.X.1891, buds, Dinklage 1391 ( P [ P 03793519]!, WAG [ WAG 0034479]!).

Distribution, ecology and phenology. – This variety occurs in southern Cameroon from Kribi to Campo, in Equatorial Guinea ( Rio Muni) and in Gabon, where it is found mostly in the northwest (Crystal Mts) with one record further south in the Chaillu massif ( Fig. 8 ). Its range locally overlaps with that of var. floribunda in Gabon and Equatorial Guinea. It grows in secondary forest regrowth, often along roads, 0–540 m in elevation.

Flowers have been recorded from March to May and October to December; fruits in August-September and from November to March.

Conservation status. – The extent of occurrence (EOO) of S. floribunda var. paucinervis is calculated to be 21,218 km ², a little above the limit for “Vulnerable” status under subcriterion B1. Its area of occupancy (AOO) is estimated to be 80 km ², which falls within the limit for “Endangered” status under subcriterion B2, but is certainly an underestimation given the low collecting density in most of its range. The taxon occurs in Atlantic Central Africa ( Cameroon, Gabon and Equatorial Guinea) and is known from 21 specimens. It is found in secondary forest habitats where it appears to be locally common, and given its ecology there is no evidence of a particular threat; consequently, it is here assessed as “Least Concern” [LC] using the IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes. – This taxon differs from other varieties by its leaves with fewer secondary veins (8–13 pairs only) and the generally sparser indumentum of its vegetative parts – the stems being glabrous or nearly so, and the leaves glabrous except on veins. Its original description is based on two syntypes, Dinklage 743 and Dinklage 1391 (B), both of which were presumably destroyed in the Second World War but have extant duplicates in P and WAG. The P sheet of Dinklage 743, which is the most complete, is chosen here as lectotype.

Additional material studied. – CAMEROON. Reg. South: Kribi-Campo, 35 km S de Kribi, 4. I.1983, imm. fr., van der Zon 1983 ( WAG); 3 km S of Kribi, Grand Batanga road, 25.X.1968, fl., Bos 3134 ( BR, K, P, WAG, YA); 5 km S of Kribi, Grand Batanga road, 26.II.1969, fr., Bos 4005 ( BR, P, WAG, YA); near Eboundja I, km 20 road Kribi-Campo, 4. I.1983, imm.fr., de Kruif 1020 ( WAG, YA); Ebundja 2, village along road from Kribi to Campo, 17.III.2007, buds, Dessein 1640 ( BR, P); 45 km on the road from Kribi to Campo, 3.XII.1974, fl., J. J. F. E. de Wilde 7784 A ( BR, WAG); 10 km ENE Ebodje, soit 40 km S Kribi, 7.XII.1979, fl., Letouzey 15322 ( BR, P, YA); Campo Ma’an National Park, 12.II.2012, fr., Sonké 5915 ( BR, MO, YA); Campo-Ma’an area, Massif des Mamelles, Along the path to Mamelles highlands, 23.IV.2001, buds, Tchouto Mbatchou et al. 3223 ( WAG); Dipikar, road to centre of Island, 7.V.2001, fl., van Andel et al. 3421 ( WAG); Campo Ma’an National Park, road Kribi-Ebodje Along small logger’s road, c. 2.7 km from Lolabé village, 4.VIII.2001, fr., van Andel et al. 3827 ( WAG).

EQUATORIAL GUINEA. Litoral: Bata-Monson-Dibolo, Estrada kms 54–55, 15.X.1991, fl., Carvalho 4887 ( BR, WAG); Bata-Mari, Estrada kms 62–63, 15.XI.1991, imm.fr., Carvalho 4949 ( WAG). Centro-Sur: 4 km N de Mitong, 12.XII.2003, buds, Sonké 3136 ( BR, BRLU, K).

GABON. Estuaire: 89 km along the road Libreville-Assok, Mts de Cristal, 14.VIII.1978, imm.fr., F. J. Breteler & J. J. F. E. de Wilde 7 ( BR, LBV, WAG); Crystal Mountains, 3 km NE of Kinguélé, 11.IX.1994, fr., F. J. Breteler et al. 12808 ( LBV, WAG); km 10 Tchimbélé-Kinguélé, 11.II.1986, fr., Breyne 5102 ( BR, LBV); Crystal Mountains, 8 km on the road Tchimbélé to Kinguélé (= 74 km on SEEG road), 15.XI.2004, fl. & fr., Wieringa et al. 5440 ( BR, K, LBV, WAG). Ngounié: Chantier Leroy, rte à 13 km de Masika vers Yeno sur rte Mouila-Yeno, 12.II.1988, imm.fr., A. M. Louis 2733 ( LBV, WAG). WoleuNtem: Tchimbélé, 0.5 km S of dam, 19.III.1990, fr., Wieringa 720 ( BR, LBV, WAG).

Figures

Fig. 7. – Sabicea floribunda var. floribunda: A. Inflorescence. Sabicea floribunda var. paucinervis Wernham: B. Fruits. Sabicea nobilis R.D. Good: C. Lower side of leaf; D. Stem with mature infructescence. Sabicea proselyta (N. Hallé) Razafim. et al.: E. Fruiting stem; F. Mature infructescence. [A: near Tchimbélé, Gabon, plant not collected; B: Sonké 5915; C–D: Texier et al. 706; E: Sonké & Zemagho 6329; F: van Valkenburg et al. 3140] [Photos: A: S. Dessein; B: B. Sonké; C–D: N. Texier; E: B. Sonké; F: J. Degreef]

Fig. 8. – Distribution map of Sabicea floribunda K. Schum. (squares: var. anisostegia O. Lachenaud, Zemagho & Sonké; stars: var. floribunda; triangles: var. paludosa O. Lachenaud, Zemagho & Sonké; circles: var. paucinervis Wernham).