Impatiens elianae S.Abramczyk & Eb.Fisch., 2015

Abrahamcyk, Stefan & Fischer, Eberhard, 2015, Impatiens elianae (Balsaminaceae), a new species from central Madagascar, with notes on the taxonomic relationship of I. lyallii and I. trichoceras, Phytotaxa 226 (1), pp. 83-91 : 83-86

Impatiens elianae S.Abramczyk & Eb.Fisch. , sp. nov. ( Figs. 1 , 2 )

Impatienti trichocerati affinis sed caule sparse-pubescenti, lamina foliorum in centro argenteo-viridi, nectariis extrafloralibus linearibus, inflorescentiis bifloribus, sepalis lateralibus longipilosis, petalo dorsali cum crista valde majore, calcare breviore et seriei pilis roseis ovarii et capsulae valde differt.

Type :— MADAGASCAR. Cult. Hort. Bot. Univ. Bonn ex Andasibe-Perinet National Park, 22.01.2015, Abrahamczyk 609 (holotype TAN!; isotypes P!, B!, BR!, BONN!). The plant was obtained from a horticultural collection from Great Britain said to have been collected at Andasibe .

Decumbent to slightly ascendant, perennial herb, up to 200 mm high. Stems rooting at lower nodes, sparsely pubescent (hairs 1.0– 1.2 mm long). Leaves spirally arranged, the petiole (9–) 18–30 mm continuously growing, sparsely pubescent; lamina (48–)54–68 × 29–36 mm, ovate to ovate-oblong, glossy with silvery part in the centre on upper surface, and very short hairs (<0.5 mm) on the veins; apex acute; base ± cuneate; lateral veins 5–7 pairs; margin crenate to crenateserrate; extrafloral nectaries 1–2 mm long, linear, 1 pair at the petiole base, 0–2 at the petiole, 0–2 at the lamina base; reduced extrafloral nectaries at the lamina margin between each pair of teeth and at the tip of the apex. Inflorescence (1- or) 2-flowered. Flowers deep pink, glossy. Bracts linear, 2–4 mm long, woolly hairy (hairs 0.8–1.2 mm long). Pedicel 40–51 mm long, pubescent (hairs 0.8–1.2 mm long). Lateral sepals 2, 4–5 mm long, linear, acuminate, pubescent (hairs 1.0– 1.2 mm long). Lower sepal 6–7 mm long, 9–11 mm deep, obliquely naviculate, densely pubescent (hairs (0.5–) 0.8–1.2 mm long), white, abruptly peaking into a green, 2(–3) mm down facing tip and abruptly constricted into a 40–44 mm, curved, filiform spur, densely pubescent throughout (hairs 0.5–1.2 mm long), light rose, becoming greenish towards the clubbed tip. Dorsal petal 11–13(–14) × 19–23 mm, obcordate, dorsally with a broad ovate crest 8–9(–10) × 7–8(–9) mm, green in the centre, densely pubescent (hairs 1.0– 1.2 mm long) throughout, peaking into a 1–2 mm long tip. Lateral united petals (14–) 16–18 mm long, with petals different in size and shape; upper petal 6–8(–10) × 10.5–13(–14) mm, narrow ovate-falcate, slightly obcordate; lower petal 11–12(–13) × 9–11(–12) mm, broad ovate-falcate, slightly obcordate. Ovary glabrous with (3–)5 rows of multicellular, pink hairs (1.0– 1.2 mm long), one on each carpel. Fruits (12–)13–14 × 6–7 mm, pear-shaped with (3–)5 rows of multicellular, pink hairs, producing 10–13 round to ovate seeds, each 1–2 × 1–2 mm.

Habitat: —Perhumid submontane forest, exact ecology unknown.

Distribution: — Madagascar, Andasibe, only known from cultivated specimens.

Eponymy: —Dedicated to Eliane Furrer-Abrahamczyk [1986–], wife of Stefan Abrahamczyk.

Notes: —The new species clearly belongs to the Impatiens lyallii complex and is closely related to I. trichoceras but it differs from the latter by its sparsely pubescent stem, relatively small, ovate to ovate-oblong, glossy lamina with silvery part in the centre, linear extrafloral nectaries, 2-flowered inflorescences, relatively long hairs on the sepals, larger size and shape of the broad ovate crest at the dorsal side of the dorsal petal, shorter spur, and the (3–) 5 rows of pink hairs on the ovary and fruit.

Figures

FIGURE 1. Impatiens elianae. A, B, flower seen from behind, C, lateral sepal, D, lower sepal and spur, E, dorsal pepal, F, detail of crest from dorsal petal, G, lateral united petals, H, ovary.All drawn from the type, Abrahamczyk 609. Artist: E. Fischer.

FIGURE 2. Impatiens elianae.A, habit with inflorescence. B, ovary; C, flower bud; D, flower, front view; E, flower, back view; F, flower, lateral view. Scale bars: A–F = 10 mm, B, C = 5 mm. From plants cultivated in Botanical Gardens University of Bonn. Photographs: E. Fischer.