Secamone, R. Br.

Klackenberg, Jens, 2001, Notes on Secamonoideae (Apocynaceae) in Africa, Adansonia (3) 23 (2), pp. 317-335 : 321-322

SECAMONE R. Br. (in Africa)

Prodr. 1: 464 (1810) & Asclepiadeae: 44 (1810), preprint of Mem. Wern. Nat. Hist. Soc. 1: 55 (1811); Benth. & Hook. f., Gen. Pl. 2: 746 (1876); Hook. f., Fl. Brit. Ind. 4: 12 (1883); K. Schum. in Engl. & Prantl, Nat. Pflanzenfam. 4(2): 261 (1895); Choux, Mém. Acad. Malgache 1: 3 (1926); Hutch. & Dalziel, Fl. W. Trop. Afr. 2: 88 (1963), Dyer, Genera of Southern African Plants 1: 485 (1975); Klack., Opera Bot. 112: 12 (1992); Goyder, Kew Bull. 47: 439 (1992); Klack., Kew Bull. 47: 597 (1992); F. Friedmann, Fl. Seychelles, Dicot.: 471 (1994). — Lectotype: Secamone emetica (Retz.) R. Br. ex Schultes (= Periploca emetica Retz. ), vide PHILLIPS (1951): 606. Rhynchostigma Bentham in Benth. & J.D. Hooker,

Hooker’s Icon. Pl. 12: 77 (May 1876); Benth.,

Gen. Pl. 2: 771 (May 1876). — Lectotype:

Rhynchostigma racemosum Bentham , vide BULLOCK

(1962): 194.

The description refers to African and Malagasy taxa, with characters found only outside continental Africa put in brackets.

Herbaceous to suffrutescent twiners to small scrambling (or erect) shrubs, underground systems poorly known. Stems terete, sometimes with chlorophyll. Leaves decussate on elongate branches (or sometimes seemingly whorled on brachyblasts), linear to ovate to broadly obovate or almost orbicular, rounded or retuse to acute to acuminate or apiculate to mucronate at the apex, truncate to tapering at the base, (usually) petiolate, glabrous to hairy, basically pinnately nerved, thin and herbaceous to coriaceous; indumentum of rather long and erect to usually shorter and appressed, sometimes reddish, hairs, (sometimes with long curved intertwined white hairs); nerves not visible to sometimes distinctly protruding at both sides when dry; epidermis smooth to sometimes tuberculate-papillate.

Inflorescences terminal to extra-axillary but often seemingly and rarely truely axillary, much shorter to longer than the adjacent leaves; cymes lax to dense with few to many or rarely solitary flowers. Flowers pentamerous, actinomorphic, from 1.5 mm to slightly more than 1 cm long. Calyx lobes linear to broadly ovate or oblong to orbicular, rounded to acute at the apex, glabrous to hairy, usually ciliate, usually with glands at the sinuses. Corolla in bud cylindric or narrowly conical to ovoid or globose, sinistrorsely or dextrorsely twisted or not twisted, valvate or usually contorted with the right or left lobemargins overlying or imbricate, fused for c. 1/7 to c. 1/2(-6/7) of their length, usually glabrous outside, glabrous to usually variously hairy to papillate inside, white to yellow or greenish; tube short and open to campanulate or longer and cylindrical to pitcher shaped; lobes erect to spreading or rotate to reflexed, linear to orbicular, rounded to obtuse to acute at the apex, entire (but sometimes with somewhat uneven wavy margin); corolline corona absent or present and consisting of more or less fleshy ridges usually forming a V at each lobe sinus or sometimes forming a cross-bar at the inner face of the corolla lobe with a small pocket formed in the very sinuses, and sometimes with the corona ridges running united below the sinuses along the sutures of the corolla lobes towards the base of the tube. Staminal column arising from the base of the corolla tube; filaments with usually long sclerified margins (which are sometimes furnished with pouch-like structures near the bases); connective produced into a membranous tip; corona lobes shorter to longer than the staminal column, laterally or dorsiventrally compressed or subulate, falcate to straight to arched over the staminal column, (rarely absent). Pollinia two in each anther-loculus, globose to narrowly ellipsoidal, attached by a caudicle to a ± semi-ellipsoidal soft corpusculum. Style absent (or rarely very short). Style head (short and not protruding to) elongated and protruding up to 3 times beyond the anthers, consisting of 2 parts; basal portion swollen, narrowing abruptly into the apical portion; apical portion entire to deeply bifid at the apex, evenly narrow to often broadened towards the apex and then club-shaped or (rarely with the upper margin thin and recurved); stigmatic surfaces localised in 5 spots on the flanks of the basal portion of the style head.

Follicles appressed to widely spreading (to reflexed), linear in outline to ovoid, glabrous to hairy. Seeds ovate, compressed, crowned with a coma of white or ivory hairs.