Impatiens elwiraurzulae Eb.Fisch., Abrah., Holstein & S.B. Janssens, 2021

Fischer, Eberhard, Abrahamczyk, Stefan, Holstein, Norbert & Janssens, Steven B., 2021, Evolution of Impatiens (Balsaminaceae) in the Albertine Rift – The endemic Impatiens purpureoviolacea complex consists of ten species, TAXON 70 (6), pp. 1273-1299 : 1288-1290

Impatiens elwiraurzulae Eb.Fisch., Abrah., Holstein & S.B. Janssens , sp. nov. –

Holotype: Democratic Republic of the Congo. Kahuzi-Biéga National Park, Mulolo , 1100 m, 10 Dec 2017, B. Dumbo & L. Dumbo s.n (BR barcode BR0000014532115 !; isotypes: BONN!, KOBL!) .

Diagnosis. – Impatiens elwiraurzulae belongs to the group with glabrous ovary. It differs from all related taxa ( I. lotteri , I. ludewigii , I. versicolor ) in the 26–35 mm long spur, that is often only slightly coiled, the entirely white flowers with yellow and very small spot-like purple marks on upper lateral petals, the leaves, stems and flowers almost glabrous, and the occurrence in mid-altitude forest at 1100 m.

Description. – Plants prostrate to ascending, stem 15– 30 cm long. Leaves, stems and flowers almost glabrous. Leaves shining vivid green on upper surface, lighter green on lower surface, petiole 11–20 mm long, with 2–3 pairs of extrafloral nectaries, lamina ovate, 45–66 × 27–39 mm, margin with 10–11 pairs of extrafloral nectaries. Inflorescence with 4–7 flowers, peduncle 2 mm long, pedicel 15–26 mm long. Flowers entirely white with yellow and very small spot-like purple marks on upper lateral petals. Lateral sepals 6–8 × 2– 3 mm. Lower sepal navicular, 10–12 mm long and 4–5 mm deep, abruptly constricted into a spiraled, usually filiform spur, spur 26–35 mm long, often only slightly coiled. Dorsal petal 10–13 × 12–15 mm. Lateral united petals up to 25 mm long, upper lateral petal 14–16 × 7–8 mm, base of upper lateral petal with dark pink or red and yellow maculae, lower lateral petal 19–21 × 8–10 mm. Ovary 4–6 mm long, glabrous. Fruit 14–15 × 5–6 mm, glabrous. Figures 2 , 5E,F , 13A–D , 14 .

Ecology. – Mid-altitude forest at 1100 m. Probably sphingophilous due to white flowers with long, relatively straight spurs.

Distribution. – Democratic Republic of the Congo, only known from Kahuzi-Biéga National Park.

Etymology. – Named after Elwira Urzula Schweizer, who supported the work of the first author.

Figures

Fig. 2. Distribution map of the eight insect-pollinated species of the Impatiens purpureoviolacea complex. Dots indicate species with hairy ovaries, and stars mark species with glabrous ovaries.

Fig. 5. Seeds of the Impatiens pur- pureoviolacea complex. A & B, Impatiens kivuensis: A, Seed; B, Detail of testa. C & D, Impatiens ×troupinii: C, Seed; D, Detail of testa. E & F, Impatiens elwiraurzu- lae: E, Seed; F, Detail of testa. — Scale bars: A, 400 μm; B, 70 μm; C, 300 μm; D, 90 μm; E, 700 μm; F, 100 μm. A & B, Fischer 13451, BG Bonn 34557; C & D, Fischer 13912, BG Bonn 37754; E & F, Dumbo & Dumbo s.n., BG Bonn 39658.

Fig. 13. A–D, Impatiens elwiraurzulae. A & C, Flower, frontal view; B, Flower, lateral view; D, Flower showing only slightly coiled spur. E, Impatiens lotteri, detail of habit with flower. — A–D, Dumbo & Dumbo s.n., Democratic Republic of the Congo, Mulolo; E, Lotter 1542, Democratic Republic of the Congo, Ulindi River (Photo: M.C. Lotter).

Fig. 14. Impatiens elwiraurzulae. A, Leaf, upper surface; B, Leaf, lower surface; C & D, Inflorescence; E, Flower; F, Lower sepal with spur; G, Dorsal petal; H & I, Lateral united petals; J, Bracts, pedicel, lateral sepals and anthers. — Scale bar: 1 cm. A–J, Dumbo & Dumbo s.n., Democratic Republic of the Congo, Mulolo.