Sabicea speciosissima K. Schum.

Zemagho, Lise, Lachenaud, Olivier & Sonké, Bonaventure, 2018, Four new species of Sabicea (Rubiaceae) from tropical Africa, with additional notes on the genus, Candollea 73 (2), pp. 277-293 : 290-291

Sabicea speciosissima K. Schum. in Bot. Jahrb. Syst. 33: 338. 1903, syn. nov.

Holotypus: CAMEROON. Southwest: Kebo , 19.VI.1899, Conrau 2 4 7 ( B †). Neotypus (designated here): CAMEROON. Southwest: forest near Boa Bakundu village , SW of Kumba , 19.IV.1986, Etuge & Thomas 60 ( BR [ BR0000018696042 ]!; isotype: MO).

= Rothmannia octomera (Hook.) Fagerl. in Arkiv För Bot. Stockh. 30A, 7: 39. 1943. ≡ Gardenia octomera Hook. in Bot. Mag.: tab. 5410. 1863. Holotypus: [ EQUATORIAL GUINEA]: “ ex Fernando Po ” [ Bioko Island ], cult. hort. Kew , X.1863, Mann s.n. ( K!).

Notes. – The original material of Sabicea speciosissima was destroyed in Berlin, and no duplicates have been found; a photograph is kept in BM, but is of very poor quality and shows only a leafy branch (the flowers being presumably hidden in a pocket). A figure of the flower has been published by WERNHAM (1914: Pl. XII.40) whose account of this species in his monograph is otherwise very brief. There are no more recent records of the species, which is not even mentioned by HEPPER (1963) in his regional treatment of the genus.

SCHUMANN (1903) describes S. speciosissima as a shrub (“ fruticosa ”) with leaves pubescent on both sides, stipules 1 cm long and abruptly acuminate from a triangular base (“ e basi late triangulari abrupte acuminatis et subulatis ”), 5-merous axillary solitary flowers, a 2-locular ovary, a calyx with tomentose linear lobes c. 3 cm long, and a tomentose corolla 10 cm long. The corolla size is much longer than in any species of Sabicea – as Schumann already noted – and the stipule shape and habit are also aberrant for the genus. Among the few genera of Central African Rubiaceae that may show solitary flowers of this size, i.e. Adenorandia Vermoesen , Euclinia Salisb. , Gardenia J. Ellis and Rothmannia Salisb. , the first two can be excluded due to their broadly foliaceous calyx lobes, strictly terminal inflorescences and 1-locular ovary, and the third owing to its very different, sheathing stipules. Thus, Rothmannia (with inflorescences not truly axillary, but often appearing so due to sympodial growth of the stem) remains the only possibility. Within this genus, the only species fitting Schumann’s description in leaf, stipule and calyx characters is R. octomera , which however has a 6- to 8-merous and even longer (16–22 cm) corolla. The possibility of an aberrant 5-merous specimen seems not unlikely, and Schumann’s description may have been based on a flower in bud, which would explain the discrepancy in corolla size – though the figure in WERNHAM (1914: Pl. XII.40) shows an open corolla, the stiffly erect position of the lobes suggests it may have been artificially opened. The photograph of the type, however poor, appears to match R. octomera , and additional support for this interpretation comes from SCHUMANN’s (1903) note that the fruits produce a black dye, used by local people to paint their faces (“apúme des Engeborenen, die sich der Beeren zum Schwarzfärben des Gesichtes bedienen”), a usage which is documented in several species of Rothmannia including R. octomera (BURKILL, 1997) .

A specimen from the same region as Conrau’s original type, and matching well the original description (except in its 6-merous flowers) is designated here as neotype.