Craterispermum rumpianum Taedoumg & Hamon, 2013

Taedoumg, H. & Hamon, P., 2013, Three new species of Craterispermum (Rubiaceae) from the Lower Guinea Domain, Blumea 57 (3), pp. 236-242 : 238-240

Craterispermum rumpianum Taedoumg & Hamon , sp. nov. — Fig. 2 ; Map 1

C. schweinfurthii Hiern propter inflorescentias subcapitatas et nervos intersecundarios subtiliter reticulatos proximum, sed ab illo differt inflorescentis sessilibus, stipulis caducis atque corollarum tubis longioribus (6.5–8 mm vs 3.7–5.8 mm in C. schweinfurthii ). — Typus: Letouzey 14521 (holo P; iso YA), Cameroon, Monts Rumpi, près de Lokando, 30 km NNW de Kumba (N4°52' E9°17'), 23 Mar. 1976 .

Etymology. The species is named after the type locality.

Shrub 1–2 m tall; all vegetative and generative parts glabrous; twigs pale brown, decurrently ridged. Stipules caducous, keeled; basal portion 4.5 – 6 mm long; tip narrowly triangular or needlelike, 1–1.5 mm long. Leaves petiolate; petioles canaliculate, 10–18 mm long; leaf blades obovate, 11.5–14.8 by 4.5 –6.1 cm, subcoriaceous, yellowish brown above, paler below; base cuneate; apex acuminate, acumen 8 –10 mm long; midrib prominent below; secondary venation prominent below and moderately prominent above, 8 –9 pairs of secondary veins, tertiary and higher order venation conspicuous, closely and irregularly reticulate on both sides. Inflorescences sessile, axillary, paired, opposite, very compact cymes consisting of three subcapitate parts, the central part sessile and less developed and the lateral ones larger and borne on short axes <1 mm long, 9–16 by 3 –10 mm, several-flowered; bracts and bracteoles very congested, triangular to ovate, c. 1.5 mm long, apex acute or obtuse. Flowers presumed heterostylous (but only longistylous morph known), 5-merous, sessile. Longistylous flowers: calyx creamy white tinged violet; tube c. 0.6 mm long; lobes triangular, c. 0.3 mm long. Corolla white; tube narrowly cylindrical, 6.5 – 8 mm long, sparsely to moderately pubescent

.

)

2001

IUCN

(

criteria

Category

List

Red

IUCN the applying by assessed sonkeanum

.

C

and rumpianum

.

C

,

deblockianum

Craterispermum of status

Conservation

1

Table at throat and in upper half of corolla tube inside: lobes c. 6 mm long, finely pubescent in the basal half, apex acute and thickened with a subapical spike-like protuberance. Stamens with anthers only half exserted from corolla tube, inserted below the level of the throat, c. 2.5 mm long, white; filaments c. 0.2 mm long. Ovary c. 2 mm long. Style exserted for c. 5 mm; stigma bilobed, stigmatic lobes c. 2.5 mm long. Young fruits dark purple.

Habitat & Ecology — Craterispermum rumpianum occurs in submontane forest with low canopy (15 – 20 m). Altitude 900– 1400 m. Flowers: March; fruits: April (immature fruits).

Distribution — Craterispermum rumpianum is endemic to Cameroon and only known from the Rumpi Hills in the South-west Region.

Conservation status — Critically endangered. See Table 1.

Critical remarks — Craterispermum rumpianum has only been collected twice. Brevistylous flowers and mature fruits were not available for description.

Taxonomic affinities — Craterispermum rumpianum and C. schweinfurthii share subcapitate, compact inflorescences and closely, irregularly reticulate venation. However, C. rumpianum differs from C. schweinfurthii by its sessile inflorescences (vs pedunculate in C. schweinfurthii ), its caducous stipules (vs persistent in C. schweinfurthii ) and the size of the corolla tube (6.5– 8 mm long in C. rumpianum vs 3.7– 5.8 mm long in C. schweinfurthii ).

Additional specimens examined. CAMEROON, Dessein, Lachenaud, Lemaire, Sonké & Taedoumg 2584 (BR, YA), south-west, Rumpi Hills near Dikome Balue, 19 Apr. 2009 .

Figures

Map 1 Distribution of Craterispermum deblockianum (●), C. rumpi­ anum (▲) and C. sonkeanum (■). Based on the specimens cited in the text.

Fig. 2 Craterispermum rumpianum Taedoumg & Hamon. a. Flowering branch; b. stipule; c. node carrying inflorescences with ovaries, calyces and flower bud; d. longistylous flower (calyx, corolla, style and stigma) (a, d: Letouzey 14521, P; b, c: Dessein, Lachenaud, Lemaire, Sonké & Taedoumg 2584, BR). — Drawn by Antonio Fernandez.