Canthium armatum (K.Schum.) Lantz

Rubiaceae, D. Bridson. Flora Zambesiaca 5:2. 1998

Morphology General Habit

Shrub or small tree 1–5(8) m tall; young branches glabrous or sometimes pubescent, often with a few lenticels, armed with spines 1–4.5 cm long, situated above brachyblasts (abbreviated lateral branches) perpendicular or upwardly angled; bark rusty-brown when young, grey when older.

Morphology Leaves

Leaves mostly restricted to brachyblasts, blades 2.8–5 × 1.4–4.5(5) cm, elliptic to ovate-elliptic (or round to broadly cordate when on main branches), obtuse to rounded at apex, shortly attenuated at base, often somewhat discolorous but not glaucous beneath, thickly chartaceous, usually glabrous or occasionally pubescent beneath; lateral nerves in 3 main pairs; tertiary nerves finely reticulate, apparent beneath; domatia present as small tufts of hair; petiole (3)5–9 mm long, slender, often pubescent above; stipules c. 1.5 mm long, triangular, apiculate, with silky white hairs inside, soon caducous.

Morphology Reproductive morphology Flowers

Flowers 4-merous, borne in pedunculate many-flowered, corymbose cymes arising from brachyblasts; peduncles 8–35 mm long, glabrous to pubescent; pedicels 3–12 mm long, glabrous to pubescent; bracts and bracteoles inconspicuous.

Morphology Reproductive morphology Flowers Calyx

Calyx tube 1–1.25 mm long, glabrous; limb 0.5–0.75 mm long, repand or shortly toothed.

Morphology Reproductive morphology Flowers Corolla

Corolla creamy-white; tube 2–2.5(3) mm long, densely choked with finely moniliform hairs at throat, those above erect and those beneath deflexed; lobes (2)3.5–3.75(4) × 1.5–1.75 mm, narrowly oblong, thickened and obtuse at apex, reflexed.

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anthers exserted but not reflexed, dorsal face covered with darkened connective tissue except for margin.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Style exceeding corolla tube by a little more than twice; pollen presenter 1–1.25 mm across, cylindrical, 3–4-lobed at apex; ovary 3(4)-locular.

Morphology Reproductive morphology Fruits

Fruit orange, 1–3(4)-seeded, 10–15 mm long, varying in shape according to number of seeds developing.

Morphology Reproductive morphology Fruits Pyrene

Pyrene 8 × 5 × 4 mm, flattened ellipsoid, clearly crested around the apex, rugulose.

Morphology Reproductive morphology Seeds

Seeds 6.75 mm long, flattened ellipsoid, ± winged at the apex.