Impatiens irvingii Hook.f.

Balsaminaceae, E. Launert. Flora Zambesiaca 2:1. 1963

Morphology General Habit

Perennial herb usually much branched; stems up to 1·5 m. long or even more, succulent, prostrate or ascending, rarely erect, red or green tinged with red, usually somewhat swollen at the nodes, glabrous or hairy (sometimes all over) with a very dense velvety indumentum.

Morphology Leaves

Leaves spirally arranged, sessile or petiolate; lamina (4) 6–13 (16) × (1) 1·5–3·5 (4·5) cm., lanceolate, oblong-lanceolate, ovate-lanceolate, oblong-elliptic or rarely elliptic, chartaceous, usually olive or dark green on the upper surface, glaucous, silvery or greyish-green on the lower one, glabrous on both surfaces or pubescent on the lower and glabrous or sparsely pilose on the upper one, or often with a very dense velvety indumentum below, apex acute or very rarely subobtuse and usually acuminate, margin crenate-denticulate or rarely serrate and sometimes ciliate towards the base, base cuneate or rarely subrounded; secondary nerves 8–13 pairs; petiole up to 3 cm. (in our region leaves subsessile in only specimen known), glabrous or more often pilose or pubescent.

Morphology Reproductive morphology Flowers

Flowers axillary, solitary or in clusters of 2 or 3, pale purple or violet; bracts up to 4 mm. long, lanceolate-triangular or subulate, acute, usually densely pilose, rarely glabrous; pedicels up to 9 cm. long, slender, pilose or glabrous.

Morphology Reproductive morphology Flowers Calyx

Lateral sepals 4–7 × 1·5–2·5 (3) mm., lanceolate to ovate-lanceolate, rarely oblong-lanceolate, acuminate, usually ± densely pilose, sometimes glabrous. Posterior sepal 9–14 mm. long, c. 2·5 mm. deep, shallowly and obliquely navicular, abruptly constricted into the spur, distally caudate, usually ± densely pilose, rarely glabrous; spur up to 5·5 cm. long, rather slender, subconical in the upper half, cylindric in the lower one, with a subacute end, ± densely pilose, rarely glabrous, strongly incurved when young, slightly incurved or often nearly straight when older.

Morphology Reproductive morphology Flowers Corolla

Anterior petal 8–15 mm. high and up to 17 mm. broad (when flattened), dorsally very narrowly cristate with crest often rim-like, apex usually entire, mucronate. Lateral united petals very variable in size, (13) 17–25 (30) mm. long, deeply 2-lobed; lobes nearly always ± overlapping, usually glabrous, rarely pubescent outside; anterior lobe 10–18 × 7–15 mm., obliquely semi-elliptic, semi-circular or rarely obovate, entire, with the lower margin usually ± straight; posterior lobe usually somewhat smaller (very rarely a little larger) than the anterior one, usually obovate, rarely subcircular, entire (see t. 26 fig. 13).

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary glabrous.

Morphology Reproductive morphology Fruits

Capsule up to 1·8 cm. long, fusiform, glabrous.

Morphology Reproductive morphology Seeds

Seeds numerous, c. 2·5 × 1·7 mm., obovate in outline, brownish, with a papillose surface, glabrous.