Pachycarpus bisacculatus (Oliv.) Goyder

Apocynaceae (part 2), David Goyder, Timothy Harris, Siro Masinde, Ulrich Meve, Johan Venter. Flora of Tropical East Africa, 2012

Morphology General Habit

Perennial herb with annual stems arising from a fascicle of fleshy fusiform tubers.

Morphology Stem

Stems erect or ascending, 0.3–1.5 m long, usually single and unbranched, but sometimes branched below, densely pubescent with spreading white hairs

Morphology Leaves

Leaves with petiole (3–)5–13 mm long, pubescent; lamina lanceolate to ovate or oblong, 6–12 × 2–7 cm, apex obtuse or slightly retuse to acute, base cordate or truncate, margins scabrid, venation prominent with numerous parallel secondary veins at right angles to the midrib, indumentum of slightly scabrid spreading white hairs on both upper and lower surfaces

Morphology Reproductive morphology Inflorescences

Inflorescences terminal and extra-axillary with 4–8(–14) flowers in a secund umbel.

Morphology Reproductive morphology Inflorescences Peduncles

Peduncles erect or ascending, (2–)4–17 cm long, densely spreading-pubescent.

Morphology Reproductive morphology Inflorescences Bracts

Bracts filiform, 5–12 mm long, pubescent.

Morphology Reproductive morphology Flowers Pedicel

Pedicels (1–)1.5–3 cm long, pubescent, tinged with purple Fruiting pedicel contorted to hold follicle erect.

Morphology Reproductive morphology Flowers Calyx

Calyx lobes lanceolate, 6–10 × 2–3 mm, acute, densely pubescent, purplish

Morphology Reproductive morphology Flowers Corolla

Corolla rotate or saucer-shaped, underside brownish purple, densely pubescent, upper surface pale green with a network of purple or chocolate brown lines particularly in the distal half, minutely papillate and with short hairs towards the apex and margins; lobes ovate, 10–15 × 7–10 mm, acute

Morphology Reproductive morphology Flowers Corona

Corona lobes 5–6 × 4–6 mm, arising from the base of the staminal column and adnate to it to the base of the anthers, cream or more usually pink with a purple tip, spreading and strongly complicate at extreme base with proximal margins parallel and erect reaching to the base or middle of the anthers, distal half or two thirds forming an erect or incurved cone with involute margins, flanges between the base of this apical cone and the proximal margins of the lobes sinuous and dilated to form a pair of shallow pouches, the upper and inward-facing parts of the lobes minutely but densely papillate, the outer faces glabrous

Morphology Reproductive morphology Flowers Androecium Stamens

Staminal column 6–8 mm long, fertile part forming a cylinder 3–4 × 4–6 mm.

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anther wings triangular, 3 × 1.5 mm, not extending below fertile part of column, giving the column a truncate conical appearance. Anther appendages 2.5–3 × 1–1.5 mm, semicircular in outline and inflexed over apex of stylar head; corpusculum black, ovoid, 0.5 × 0.2 mm; translator arms ± 0.8–1 × 0.15 mm, flattened and geniculate, with a further 0.3–0.4 mm clasping overlap with the pollinium.

Morphology Reproductive morphology Flowers Pollinia

Pollinia irregularly clavate in outline, 1.4–1.6 × 0.7 mm, flattened

Morphology Reproductive morphology Flowers Gynoecium Style

Stylar head flat, white or green

Morphology Reproductive morphology Fruits

Follicle ovoid or fusiform, to 12 × 7 cm, generally inflated, without wings or processes, pubescent

Morphology Reproductive morphology Seeds

Seeds (immature) ovate, 4.5 × 3 mm, with a verrucose disc and a narrow inflated rim; coma ± 3 cm long

Figures

Fig. 106/9–10, p 439

Ecology

Seasonally waterlogged grassland and Brachystegia or mixed deciduous woodland; 100–2500 m

Note

Field observations in Zambia and Tanzania by Bullock and Milne-Redhead in K.B. 8: 333 (1953) show that the flowering periods of this species (referred to as P. lineolatus) and the closely related P. lineolatus (referred to as P. schweinfurthii) differ by about six weeks.

Distribution

Range: Widespread from Guinea Bissau to South Sudan and Ethiopia and S to Angola and Mozambique Flora districts: U1 U2 U3 U4 K3 K5 K7 T1 T2 T4 T6 T7 T8