Sabicea segregata Hiern

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 : 140-142

8. Sabicea segregata Hiern in Oliv., Fl. Trop. Afr. 3: 77. 1877

( Fig. 2G–H , 13C–F ).

≡ Pseudosabicea segregata (Hiern) N. Hallé in Adansonia ser. 2, 3: 172. 1963.

Lectotypus (designated here): GABON or EQUATORIAL GUINEA: River Muni , VIII. 1862, Mann 1766 ( K [ K000414626 ]!; isolectotype: P [P00077599]!).

= Sabicea henningsiana Büttner in Bot. Vereins Prov. Brandenburg 31: 79. 1889. Lectotypus (designated here): GABON. Estuaire: Sibangefarm, IX.1884, fl., Büttner 437 ( K!). Syntypus: GABON. Estuaire: Sibangefarm, X.1884, Büttner 443 ( B †).

Distribution, ecology and phenology. – This species occurs in southern Cameroon where rare, Equatorial Guinea ( Rio Muni), Gabon where very common and widespread (though absent in southeast, extreme northeast, and lower Ogooué basin), and southwestern Republic of Congo ( Fig. 14 ). It is found in secondary forest, edges and regrowth, and in fringing forest on inselbergs, always on drained soils, on various substrates (sandy or clayish), 0–1080 m in altitude.

Flowers and fruits have been recorded in all months.

Conservation status. – The extent of occurrence (EOO) of S. segregata is estimated to be 250,602 km ², and its area of occupancy (AOO) to be 396 km ². The latter value falls within the limit for “Vulnerable” status under criterion B2, but is an obvious underestimation given the low collecting density in most of its range and the fact that the species is generally common there. The species occurs from south Cameroon to the Republic of Congo, and is known from 124 specimens representing 71 subpopulations. It occurs in several protected areas: Campo Ma’an National Park in Cameroon, Monte Alén National Park in Equatorial Guinea, Lopé, Waka, Doudou Mountains and Ivindo National Parks in Gabon, and Dimonika Biosphere Reserve in the Republic of Congo. In view of its wide distribution, abundance, and preference for degraded forest habitats, it is here assessed as “Least Concern” [LC] using the IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes. – This species is closely related to S. floribunda , both having the corolla lobes brown at anthesis, unlike other species of the group. The differences between them are summarised in the key. The calyx lobes of S. segregata are usually longer and narrower than in other species of the group, but there is limited overlap with S. floribunda in this character.

Most collections of S. segregata , including the type, have stems with appressed hairs, but a variant with hirsute stems occurs in Gabon, particularly in the east of the country. The fruits apparently turn from whitish to red to purple-black; however, since the last colour is much less commonly reported than the other two, it is not sure whether this sequence is always followed.

The original description of S. segregata ( HIERN, 1877) does not mention the type number, but the only possible candidates are Mann 1766 in Kew, and Mann s.n. in Paris, the latter being almost certainly an unnumbered duplicate of the former. The Kew sheet is here selected as lectotype. It is not known on which side of the Muni River, which forms the border between Equatorial Guinea and Gabon, this material was collected.

The description of S. henningsiana ( BÜTTNER, 1889) is based on two syntypes, Büttner 437 and Büttner 443, both from Sibang in Gabon. The original sheets of both specimens have presumably been destroyed in Berlin, but a duplicate of the former remains in Kew, and is here selected as lectotype.

Additional material studied. – CAMEROON. Reg. South: Campo-Ma’an area , Ebodje , Along the beach , 20.II.2000, fr., Elad et al. 1367 ( WAG); Campo-Ma’an area , Mvini , Bigan , Along Trasect 7, 16.II.2000, imm.fr., Tchouto Mbatchou et al. 2524 ( WAG); Bipindi , s.d., buds, Zenker s.n. ( BR, P).

EQUATORIAL GUINEA. Centro-Sur: Parc National de Monte Alen , dalle rocheuse d’Engong , 5 km à l’W du village d’Engong, 12.V.2002, fr., Parmentier & Esono 2781 ( BRLU); 4 km N de Mitong, 12.XII.2003, imm.fr., Sonké 3138 ( BR, BRLU, K); 6 km N de Mitong, 12.XII.2003, fl., Sonké 3151 ( BR, BRLU, K); Engong , 14.VIII.2001, fl., Sonké & Esono 2546 ( BR, BRLU, WAG); Engong , 14.VIII.2001, fr., Sonké & Esono 2552 ( BR, BRLU, WAG). Litoral: Bata-Monson-Dibolo : Estrada kms 54– 55 , 15.X.1991, fl., Carvalho 4889 ( BR, BRLU, WAG); Bata-Nasanga : Estrada km 14 , 17.X.1991, fl., Carvalho 4890 ( WAG); Bata-Mari : Estrada kms 62– 63 , 15.XI.1991, imm.fr., Carvalho 4952 ( WAG); Engong , 28.VII.1999, fr., Eneme 439 ( BRLU); Etembue , 15.IX.2001, buds, Esono & Ndong 335 ( BRLU); Ndote Nord , 28.VIII.1997, fr., Lisowski M-153 ( BRLU). Reg. unknown: Akanabot , 15.IX.2001, fr., Esono & Ndong 351 ( BRLU).

GABON. Estuaire: Mondah Forest on Cape Esterias , c. 22 km on the road from Libreville, 3.IX.1978, fl. & fr., F.J. Breteler et al. 408 ( BR, K, WAG); plantations de Assoukou , près du poste de Kango , 2.X.1912, buds, Chevalier 26847 ( K, P); plantation Stéphane , sur la Bokoué , 9.X.1912, fl., Chevalier 26989 ( P); vieux chantier ‘Sango’ , Ntoum , 9.X.1987, fl., Dibata 320 ( BR, WAG); Nkoulounga , 31.I.1961, fl., N. Hallé 1024 ( P); sine loco, 15.X.1896, fl., Klaine 100 ( P); sine loco, 12.IX.1896, fl., Klaine 123 ( P); Env. de Libreville , 18.VIII.1898, fl. & fr., Klaine 377 ( P); env. de Libreville , 1897, fr., Klaine 771 ( P); Env. de Libreville , 15.VI.1897, fr., Klaine 962 ( P); env. de Libreville , 5.X.1901, fl. & fr., Klaine 2432 ( BR, K, P); km 31 Kougouleu-Atogafina , NE of Kouamé , 19.XI.1982, imm.fr., Leeuwenberg 12554 ( LBV, WAG); rte Cap Santa-Clara , 6 km à droite, 31.I.1985, fr., A.M. Louis & J.M. Reitsma 1677 ( BR, LBV, WAG); Forêt Classée de la Mondah , 0°32'48"N 9°19'40"E, 20.II.1994, fr., Lowry 4566 ( LBV); c. 15 km N. of Libreville, 18.III.1987, fr., J.M. & B. Reitsma 3166 ( LBV, WAG); forêt de la Mondah . 5 km on off road to Santa Clara from Cap Esterias road, 11.XI.1988, fl., van der Maesen et al. 5440 ( WAG). Haut-Ogooué : concession CEB, W of Okandja , 19.XI.2015, imm. fr., Texier & Akouangou 174 ( BRLU). Moyen-Ogooué : Mabounié , à 45 km au SW de Lambaréné, rives de la Ngounié , 15.X.2012, fl., Bidault et al. 845 ( BRLU, LBV, P); ibid. loco, 16.X.2012, buds, Bidault et al. 906 ( BRLU, LBV); ibid. loco, 15.XI.2013, fl., Bidault et al. 1316 ( MO); au S de Lambaréné , entre 5 et 10 km depuis la ville, entre l’Ogooué et la rte de Fougamou , 13.IV.2015, fr., Bidault et al. 1922 ( BR, BRLU); Concession forestière GWT ( Global Wood and Trading ), 5.VI.2012, imm.fr., Boupoya & al. 744 ( BRLU); Mboumi , 16.I.2000, fr., Champluvier 6008 ( BR); ibid. loco, 16.I.2000, fr., Champluvier 6019B ( BR); c. 10 km NNW of Ndjolé, on BSO forestry road , 26.II.2008, fl., Dessein et al. 2148 ( BR, LBV, MO, WAG); Ayem , 10 km SW de Ndjolé, 11.IV.1963, fl., N. Hallé 1621 ( P); Ayem , 10 km SW de Ndjolé, 30.IV.1963, fl. & fr., N. Hallé 1952 ( P); Ayem , 10 km SW de Ndjolé, 6.V.1963, fl., N. Hallé 2007 ( P); N of lake Azingo , 4.VI.2014, imm.fr., Libalah & Ikabanga 3 ( BR, BRLU); Mabounié, 18.X.2012, fl., Sonké et al. 6108 ( BR, BRLU); ibid. loco, 23.X.2012, fl., Sonké & Ikabanga 6127 ( BR, BRLU); ibid. loco, 23.X.2012, fl., Sonké & Ikabanga 6137 ( BR, BRLU); ibid. loco, 23.X.2012, fl. & fr., Sonké & Ikabanga 6139 ( BR, BRLU, P); Rougier Logging Concession , Haut Abanga. East of Ndjolé , 17.II.2012, fr., Stévart et al. 4301 ( BRLU, LBV, P); Ndjolé, I.1895, fr., Thollon 117 ( P); roadside between Ndjole town and railway station , 22.VII.1986, fr., Thomas & Wilks 6589 ( LBV, P, WAG). Ngounié : Waka forest exploitation road , 19.XI.1984, fl., Arends et al. 301 ( BR, K, LBV, P, WAG); PN de Waka , 1°10'34"S 11°08'02"E, 28.XI.2007, imm.fr., Boussengui-Nongo et al. 313 ( LBV); Mouyanama falls , at base of Mt Songou , 22.II.2008, fr., Dessein et al. 2041 ( BR, LBV); entre Pagha & Mouteti , 26.XI.1924, fl., Le Testu 5104 ( BM, BR, K, P, WAG); Parc national de Waka , près du Camp Oghoubi , 24.VI.2006, fr., J. Mayombo et al. 1559 ( LBV); 25 km on the road Ikobey to Egoubi camp, 1.IV.2004, fr., Wieringa et al. 5204 ( LBV, WAG); road Mouila to Yeno , c. 2 km before Issinga, 8.III.2013, fr., Wieringa et al. 7169 ( WAG). Nyanga : rte Tchibanga-Ndende , 25.X.2009, fl., Bissiengou et al. 540 ( BR, LBV, WAG); 48 km SSW of Doussala, road Doussala-Igotshi , 21.III.1988, fr., J.J.F.E. de Wilde et al. 9485 ( BR, K, LBV, WAG); Tchibanga , IX.1915, fl., Le Testu 2120 ( BM, BR, K, P); concession SFN , 30.X.2003, fl. & imm.fr., van Valkenburg et al. 2523 ( BR, K, LBV, P, WAG); forestry concession of Bakker , 6 km N of Igotchi, 29.X.2003, fl., Wieringa et al. 5025 ( BR, K, LBV, WAG); forestry concession of Bakker , 15 km NNE of Igotchi, 31.X.2003, fl., Wieringa et al. 5047 ( LBV, WAG). Ogooué-Ivindo : concession forestière Rougier-Ivindo . En bordure du fleuve , au N de la concession , 29.X.2015, fl., Bidault et al. 2269 ( BR); Mintoume, 5.II.2005, fr., Boupoya & Mbazza 185 ( BRLU); station de recherche de Mpassa , 10 km S de Makokou, 9.III.1984, fl., Doumenge 191 ( LBV, P); M’passa , Ile aux chauve-souris , 17.III.1977, fr., Florence 55 ( LBV, P); M’passa , 1.VI.1977, fl., Florence 496 ( LBV, P); La Nké , ancienne zone d’exploitation , 8.X.1983, buds, Floret et al. 1732 ( WAG); piste du Bouéni , 20 km SE Makokou, 11.II.1961, fr., N. Hallé 1131 ( P); Makokou, Mission Catholique , 16.II.1961, imm.fr., N. Hallé 1185 ( P); ± 50 km SE Makokou, 19.X.1964, buds, N. Hallé 2695 ( P); 9 km SSW of Makokou, near Ivindo R. , right bank , 2.XI.1977, fl., Leeuwenberg 11418 ( BR, K, WAG); Mintome, 30.III.2003, fr., Mboma et al. 64 ( LBV, WAG); Ivindo National Park , rte Langoué , 11.IV.2004, fr., Moungazi 1557 ( BR, LBV, WAG); Ivindo National Park , Massouna 2000 , 0°08.90'S 12°27.10'E, 6.XII.2003, imm.fr., D. Nguema Ekomo 507 ( LBV) & 508 ( LBV); bac de l’Ogooué , 19.VIII.1983, imm.fr., Sita 4964 ( LBV); Kongou waterfall area , 00°17'25"N 012°34'22"E, 8.II.2018, imm.fr., Texier et al. 2282 ( MO); Lopé, West Woods , 26.X.1990, buds, L. White 172 ( LBV); Lope Reserve , 15.X.1995, buds, L. White 1495 ( LBV, WAG). Ogooué-Lolo : Bambidie , c. 30 km E of Lastoursville, 2.V.1992, fl., F.J. Breteler et al. 11248 ( LBV, WAG); Makande surroundings , c. 65 km SSW of Booué, 2.II.1999, imm.fr., F.J. Breteler et al. 14892 ( WAG); Makandé, débardage Héron , 20.XI.1993, fl., Dhetchuvi et al. 1372 ( BRLU); Vers 10 km rte Makandé-Gongué, 3.XII.1993, fl. & imm.fr., Dhetchuvi et al. 1597 ( BR, BRLU, K, WAG); Lastoursville, concession forestière CEB , 30.XI.2012, fl., Ikabanga & Haurez 343 ( BRLU); c. 50 km SE of Achouka, old forest in Région des Abeilles , 17.XI.1983, fl., A.M. Louis et al. 756 ( BR, K, P, WAG); Camp Makande , 16.XII.1993, imm. fr., Moungazi 967 ( LBV); Camp concession SEEF , area of Mount Ngouadi , 00°16'12"S 013°05'00"E, 10.III.2017, fr., Texier et al. 707 ( LBV, MO); ibid. loco, 00°17'20"S 013°10'40"E, 11.III.2017, fl., Texier et al. 795 ( LBV, MO); ibid. loco, 11.III.2017, fr., Texier et al. 798 ( LBV, MO); SIAEFG logging concession , 30 km N of Pana, 01°28'44"S 12°32'55"E, 9.XII.2017, fl., Texier et al. 1564 ( LBV, MO); S of Road Lopé-Lastoursville , c. 60 km , 00°43'21"S 012°28'30"E, 18.XII.2017, imm.fr., Texier et al.1761 ( LBV, MO). Ogooué-Maritime : Toucan , 12.X.2002, fl., Bourobou et al. 993 ( LBV, P, WAG); Rabi , c. 1°55'S 9°52'E, 13.X.2002, fr., Bourobou et al. 1022 ( LBV); Gamba, 24.IX.1968, buds, Breteler & van Raalte 5675 ( BR, WAG); Foot of Doudou Mountains , 25–35 km W of Mandji, 15.II.2008, fr., Dessein et al. 1862 ( BR, LBV); between Rabi and Echira , 27.III.1990, fr., F.J. Breteler et al. 9557 ( LBV, WAG); Rabi-Kounga , near Rabi 44, 1.I. 1994, fr., Haegens & van der Burgt 226 ( LBV, WAG); Rabi-Kounga , 15.X.1991, fr., Schoenmaker 33 ( WAG); Pechoud road southwards , 27.X.1990, fl., van Nek 124 ( BR, LBV, WAG); Rabi , 4½ km on road to Divangui ., 4.III.1994, fr., Wieringa & Haegens 2387 ( BR, LBV, WAG). Woleu-Ntem : c. 6 km SSW of Mitzic, FOREENEX forest exploitation , 6.XI.2009, fl., Bissiengou et al. 703 ( LBV, WAG); Parc des Monts de cristal , 13.II.2010, fl., Bissiengou & Niangadouma 975 ( LBV, WAG); between Zomoko and Saint Germain , c. 10 km SE of Mitzic, 17.IV.1988, fr., F.J.Breteler & Dibata 8771 ( BR, K, LBV, WAG); 5–10 km E of Saint Germain, E of Okano River , 20.IV.1988, fl., F.J. Breteler & Dibata 8866 ( BR, K, LBV, WAG); Mts de Cristal , inselberg Milobo , 10km N Mbé Akélayong, 50km W Medouneu, 3.XII.2001, fl., Degreef 254 ( BR); SEEG road near Tchimbélé , pylone 7 , 6.II.2008, fr., Dessein et al. 1723 ( BR, LBV); Angoum, VII.1933, buds, Le Testu 9199 ( BM, P); Along forestry road Oveng-Mitsic , 28.III.1985, fl., J.M. Reitsma & B. Reitsma 731 ( LBV, WAG); Tchimbélé Dam, Crystal Mountains , road N. of dam ., 12.XI.2000, fl., Walters et al. 499 ( BR, LBV, WAG).

REPUBLIC OF CONGO. Kouilou: rte de Dimonika à Pounga , 24.XI.1978, fr., Cusset 520 ( K, P, WAG); env. de Dimonika , M’Bulu Pambu , 7.III.1980, fr., Cusset 956 ( P); env. de Dimonika , après Makaba carrefour , 13.XII.1982, fr., Cusset 1173 ( P); Makaba, ancien village Manengue , 17.II.1987, fr., de Foresta 1296 ( P); rte de Sounda ( Pointe-Noire ), 8.II.1966, imm.fr., Farron 5024 ( P); near Koulila , 6.XII.1990, imm.fr., LaCroix 5005 ( K); Kakamoeka , 11.X.1990, buds, Lisowski B-8005 ( BR, K, WAG); en allant vers Makaba , village à 17 km de Dimonika, 4.XII.1972, fr., Makany 2045 ( P); N’Tiétié , forêt à 3 km du village, 8.XII.1974, fl., Sita 3807 ( BR, P). Niari: Mayombe au col de Bamba , 8.XII.1990, fl. & imm.fr., Dowsett-Lemaire 1392 ( BR).

Figures

Fig. 2. – Seeds of Sabicea spp. viewed in electron microscopy. Sabicea proselyta (N. Hallé) Razafim. et al.: A. Entire seed; B. Detail of seed surface. Sabicea rubiginosa O. Lachenaud, Zemagho & Sonké: C. Entire seed; D. Detail of seed surface. Sabicea sanguinosa subsp. sanguinosa: E. Entire seed; F. Detail of seed surface. Sabicea segregata Hiern: G. Entire seed; H. Detail of seed surface. [A–B: van Valkenburg et al. 3140; C–D: Lachenaud et al. 2105; E–F: A. M. Louis & Reitsma 2004; G–H: J.J.F.E. de Wilde et al. 9485] [Photos: I. van der Beeten]

Fig. 13. – Sabicea sanguinosa subsp. viridis O. Lachenaud, Zemagho & Sonké: A. Inflorescence (short-styled flowers); B. Mature infructescence. Sabicea segregata Hiern: C. Flowering stem; D. Detail of inflorescence with short-styled flowers; E. Stem with immature fruits; F. Mature infructescence. [A–B: Lachenaud et al. 1918; C: Dessein et al. 2148; D: Bidault et al. 1316; E: Dessein et al. 1862; F: Sonké & Ikabanga 6139] [Photos: A: O. Lachenaud; B: D.I. Lafferty; C, E: S. Dessein; D: E. Bidault; F: B. Sonké]

Fig. 14. – Distribution map of Sabicea segregata R.D. Good.