Oncinotis tenuiloba Stapf

Apocynaceae, A. J. M. Leeuwenberg and F. K. Kupicha et al.. Flora Zambesiaca 7:2. 1985

Morphology General Habit

A large, strong liane reaching 30 m. or more in the crowns of trees, or a scrambling shrub, with light ochraceous thick corky bark and plentiful milky latex.

Morphology Stem

Stems flexuose, at first usually reddish-brown or greyish puberulous with a mixture of simple and branched hairs, later glabrescent with conspicuous whitish dot-like lenticels.

Morphology Leaves

Leaves membranous, drying ± concolorous green; petiole 5–10 mm. long, puberulous; 2 minute oblong or triangular glands present on upper leaf surface at proximal end of midrib; lamina 6·2–13 x 2–5 cm., narrowly obovate or obovate-oblong, the apex cuspidate-acuminate, the base rounded to acute; upper leaf surface glabrous, with major nerves both raised and channelled; lower surface glabrous (except for domatia), with all nerves raised; domatia (dense tufts of hispid hairs) present on lower leaf surface in the angles between lateral nerves and midrib, and also sometimes where lateral nerves meet.

Morphology Leaves Leaf veins

Venation: lateral nerves few (2–5 on each side), at an acute angle to the midrib; tertiary veins scalariform, ± at right angles to the midrib.

Morphology Reproductive morphology Inflorescences

Panicles axillary, many-flowered, loose; flowers greenish.

Morphology Reproductive morphology Flowers Calyx

Calyx 2–3 mm. long, lobes shortly connate at base, imbricate, elliptic, puberulous.

Morphology Reproductive morphology Flowers Corolla

Corolla lobes 3–5 mm. long, narrowly linear, ± glabrous. Corolla tube c. 3 mm. long, barrel-shaped, pubescent externally, densely pilose internally except for a narrow glabrous band at base and apex, the hairs pointing downward; 5 small triangular scales present at mouth, one in each sinus between the petal lobes.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens inserted almost at base of corolla tube; filaments short; anthers large (2–2·75 mm. long), reaching almost to mouth of corolla tube, each comprising a sagittate sterile structure bearing the anther thecae on its inner side on the upper half, the five anthers lightly connate by their margins into a tube round the gynoecium.

Morphology General Scales

Five square scales present on the receptacle centripetal to and alternating with stamens, reaching half-way up the ovary.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary of 2 ± free carpels c. 0·5 mm. long; style ± absent; clavuncle fusiform, style of 2 short fleshy lobes.

Morphology Reproductive morphology Fruits

Fruit a divaricate pair of follicles, each up to 25 cm. long and 1·3 cm. in diameter, narrowly cylindrical, tapering at both ends, brown-pubescent outside, smooth, glabrous and yellow within, splitting longitudinally at maturity, containing ¥ seeds.

Morphology Reproductive morphology Seeds

Seed c. 14 x 2·5 mm., narrowly ellipsoidal, strongly compressed, with apical coma of fine white simple hairs up to 3 cm. long.

Apocynaceae, E.A. Omino. Flora of Tropical East Africa. 2002

Morphology General Habit

Climbing shrub or liana 1.8–30 m high; bark light yellow-orange, thick, corky; inner bark with rope-like fibres; wood creamy; branches pale to dark brown, with many whitish lenticels; branchlets brownish to greyish green, puberulous to pubescent.

Morphology Leaves

Leaves petiolate; blade obovate, (1.8–)4.6–14.5 cm long, 1.2–5.5 cm wide, acuminate, rarely emarginate at the apex, base cuneate, glabrous, rarely pubescent, with 2–7 pairs of secondary veins; tertiary venation conspicuous, scalariform; domatia of pits with a dense tuft of hispid hairs along the margin; petiole 5–12 mm long, puberulous or pubescent, with 2 pairs of glands along the adaxial side, one pair near the proximal end of the midrib.

Morphology Reproductive morphology Inflorescences

Inflorescence 2.5–6.5 cm long, rusty brown-pubescent; bracts up to 3.1 mm long; pedicels 1.2–4 mm long.

Morphology Reproductive morphology Flowers

Flowers with sepals elliptic to triangular, 1.2–3.2 mm long, 0.8–1.5 mm wide, rusty brown pubescent or puberulous; corolla yellow-green, tube barrel-shaped, 2.5–3.8 mm long, lobes 3–7.3 mm long, 0.7–1.5 mm wide, glabrous or puberulous outside; corona 0.4–1 mm long; stamens inserted 0.5–1 mm from the base of the tube; pistil 2.8–3.3 mm long; style 0.1–0.3 mm long; ovules 15–45 in each carpel.

Morphology Reproductive morphology Fruits

Fruits pendulous, narrowly cylindrical, tapering at both ends, 10.5–30 cm long, 0.4–1.3 cm wide, greyish to dark brown-pubescent; seeds up to 35 in each follicle; seed 12–23 mm long, coma 25–58 mm long.

Figures

Fig. 35 (p. 108).

Habitat

Rainforest or swamp forest, riverine forest and secondary forest; 0–1500 m

Distribution

K3 K4 K7 P T1 T2 T3 T4 T6 T7 U2 U3 U4 Z