Impatiens kivuensis Eb.Fisch., Abrah., Holstein & S.B. Janssens

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 : 1282-1285

Impatiens kivuensis Eb.Fisch., Abrah., Holstein & S.B. Janssens , nom. & stat. nov.

≡ Impatiens purpureoviolacea var. longicalcarata G.M.Schulze in Bull. Jard. Bot. Etat´Bruxelles 18: 270. 1947, non Tardieu in Notul. Syst. (Paris) 11: 184. 1944 –

Holotype: Democratic Republic of the Congo, entre Kasindi et Lubango ( Kibale-Ituri ), chaîne W du Lac Edouard , ruisseau dans la forêt de montagne, 2340 m, Jan 1932, J. Lebrun 4760 (B barcode B 10 0153418 !; isotypes: BR barcodes BR0000008864574 !, BR0000008864581 !) .

Diagnosis. – Impatiens kivuensis belongs to the group with hairy ovary. It differs from I. purpureoviolacea in the beige-brownish pubescent ovary and fruit, the purple maculae on lateral united petals being larger, the upper lateral petals slightly bent upwards and not largely overlapping with lower lateral petals, the upper lateral petal 11–17 × 6–9 mm, the lanceolate leaf lamina, 55–90 × 22–42 mm, with 25–39 pairs of extrafloral nectaries, and with acuminate apex, the inflorescence with 3 flowers, the (20) 30–40 mm long peduncle, and the 13–22 mm long pedicel.

Description. – Plants ascending to erect, usually densely pubescent on stems and lower surface of young leaves, stems (33) 60–100 cm long. Leaves discolourous, dark green on upper side, pale green on lower side, petiole 12–17 mm long, hairy, with 0–2 pairs of extrafloral nectaries, lamina lanceolate or ovate, 55–90 × 22–42 mm, upper leaf surface sparsely hairy, lower surface with brownish hairs on the veins, margin with 25–39 pairs of extrafloral nectaries. Inflorescence with 3 flowers, peduncle (20) 30–40 mm long, pedicel 13–22 mm long, bracts linear-filiform, (5) 7–8 × 0.5–0.8 mm. Flowers pink, petal base barely yellow, purple maculae at base large. Lateral sepals 5–6 × 1 mm. Lower sepal navicular, 8–9 mm long and 5–9 mm deep, abruptly constricted into a spiraled, usually filiform spur, 10–12 mm long. Dorsal petal 12–14 × 12–17 mm, emarginated at apex, with dorsal crest of 8–9 mm ending in an 1 mm long spur. Lateral united petals 23–25 mm, base of upper lateral petal with purple maculae, upper lateral petals 11–17 × 6–9 mm, slightly bent upwards and not largely overlapping with lower lateral petals, lower lateral petals 12–16 × 9–12 mm. Ovary beige-brownish pubescent, 5–6 mm long. Fruit beige-brownish pubescent, 11– 14 × 6–7 mm. Figures 2 , 5A,B , 8 .

Ecology. – Montane forest, 2100–2300 m.

Distribution. – Democratic Republic of the Congo: mountains W of Lake Edward; Burundi: Kibira National Park.

Etymology. – Named after the Kivu region of eastern Congo and Burundi.

Specimens examined. – Democratic Republic of the Congo. Mt. Musimba (Tshiaberimu), 18 Apr 1935, 2300 m, De Witte 12161 (BR) . Burundi. Lacs Edouard et Kivu. Kibira National Park. Bugarama (Muramvya), S03°13′ E29°31′, 2200 m, 22 Dec 1965, Lewalle 116 (BR) ; forêt de Kibira, km 40 sur la route Bujumbura–Astrida (= Butare, Huye), 2200 m, 18 Feb 1961, Hendrickx 8024 (BR) ; Muramvya, Bugarama, 2100 m, 7 May 1970, Lewalle 4606 (BR) ; Teza, prov. Muramvya, S03°13′ E29°33′, 2100 m, 8 Dec 1977, Reekmans 6689 (BR) ; Mt. Teza, 2100 m, 4 Mar 2013, E. Fischer 13451 (KOBL) .

Notes. – Here we raise the status of Impatiens purpureoviolacea var. longicalcarata to specific rank. As the name Impatiens longicalcarata Tardieu ( Tardieu-Blot, 1944: 184) already exists, we propose the replacement name I. kivuensis , referring to the distribution of the species in the Kivu region of the eastern Democratic Republic of the Congo and northwestern Burundi.

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. 8. Impatiens kivuensis. A & C, Details of habit; B, Flower, frontal view; D, Flower, lateral view. — A–D, Fischer 13451, Burundi, Kibira National Park, Mt. Teza.