Impatiens superglabra (Grey-Wilson) 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 : 1294-1297

Impatiens superglabra (Grey-Wilson) Eb.Fisch., Abrah., Holstein & S.B.Janssens , comb. & stat. nov.

≡ Impatiens gesneroidea var. superglabra Grey-Wilson in Kew Bull. 33: 642. 1979 –

Holotype: Democratic Republic of the Congo. Mt. Kahuzi, W of L. Kivu , 13 Sep 1959, Cambridge Congo-Expedition 1959 467 (BM barcode BM000797579 !, isotype: BR barcode BR0000008863881 ! ).

Diagnosis. – Impatiens superglabra differs from I. gesneroidea in the coriaceous lanceolate-ovate leaves, almost glabrous above, and hairy below, the stem densely covered with hairlike brownish scales, the flowers with bucciniform winered lower sepal tapering into greenish spur, swollen at apex, ± glabrous, the dorsal petal wine red with greenish crest, the lateral united petals uniformly wine red, ovary and fruit pubescent, and the occurrence only in the bamboo-zone, and the ericaceous shrub to paramo from 2500–3350 m altitude.

Description. – Plants erect or ascending, stem 40–95 cm long, stems densely covered with hairlike brownish scales. Leaves coriaceous, upper leaf surface dark green, almost glabrous, lower surface light green above, hairy, petiole glabrous above, hairy below, 9–17 (20) mm long, without extrafloral nectaries, leaf lamina lanceolate-ovate, 41–53 × 19–22 mm. Inflorescence with 1 (2) flower, glabrous to very sparsely hairy, peduncle up to 8–9 mm long, bracts 1.6 × 0.5 mm, pedicel 11– 12 mm long. Flowers with bucciniform wine-red lower sepal tapering into greenish spur, swollen at apex, ± glabrous or very sparsely hairy, dorsal petal wine red with greenish crest, lateral united petals uniformly wine red. Lateral sepals green, 6– 7 × 1.5 mm, sparsely hairy, keeled. Lower sepal 9–10 mm long and 6–7 mm deep, tapering into 4–5 mm long spur. Dorsal petal cucullate, 8–10 × 4 mm. Lateral united petals 8–9 mm long, upper petal 6–7 × 3–4 mm, lower petal 7–8 × 3.5 mm. Ovary pubescent, 4 mm long, with 5 tufts of white hairs. Figures 3 , 18 .

Ecology. – Bamboo-zone, ericaceous shrub to paramo, 2500–3350 m.

Distribution. – Democratic Republic of the Congo: Mt. Kahuzi, Mt. Biéga, Mt. Muhi.

Etymology. – Named after the almost glabrous upper leaf surface.

Specimens examined. – Democratic Republic of the Congo. Lacs Edouard et Kivu. Kahuzi-Biéga National Park. Mt. Kahuzi en son flanc Nord. Arête Kabushwa. km 28 route Kavumu-Walikale, 3200 m, 8 Jan 1956, Pierlot 1226 (BR) ; Kahuzi, Dec 1945, Hendrickx 3637 (BR) ; montagnes à l’ Ouest du Lac Kivu. Massif du Kahuzi, 1929, Humbert 7754 (BR) ; Kahuzi, Nov 1946, Hendrickx 4281 (BR) ; sommet du Kahuzi, 24 May 1960, Petit 320 (BR) ; Mt Kahuzi, Jul 1945, Hendrickx 3212 (BR) ; sommet du Mont Kahuzi, 29 Dec 1971, Troupin 14279 (BR) ; flanc sud du Kahuzi, 21 Jan 1970, Ern 134 (BR) ; Mt. Kahuzi, km 28 route Kavumu–Walikale, le long de la piste allant au sommet du mont, 8 Jan 1956, Pierlot 1224 (BR) ; Kahuzi en son flanc Nord, arête Kabushwa, km 28 route Kavumu–Walikale, 8 Jan 1956, Pierlot 1225 (BR) ; Kahuzi, 17 Apr 1938, Hendrickx 288 (BR) ; Kahuzi-Gipfelzone, 18 Jan 1955, Stauffer 1057 (BR) ; Mont Kahuzi, 4 Jun 1971, Ntakiyimana 61 (BR) ; Mt. Kahuzi sommet, 3 Nov 1940, Hendrickx 1233 (BR) ; Mt. Kahuzi, km 28 route Kavumu–Walikale, le long de la piste allant au sommet du mont, 8 Jan 1956, Pierlot 1223 (BR) ; Mont Kahuzi, 11 Jul 1951, Pierlot 205 (BR) ; flanc sud du Kahuzi, 21 Jan 1970, Ern 133 (BR) ; Mt. Kahuzi, 20 Feb 1953, 3200 m, Pierlot 498 (BR) ; Mont Kahuzi, flanc sud, 25 Dec 1971, Bamps 2876 (BR) ; Mont Kahuzi, 7 May 1971, 2700 m, Ntakiyimana 13 (BR) ; Mt. Kahuzi, ericaceous shrub, c. 3000 m, 7 Oct 2009, Fischer 9765 (KOBL) ; du ruisseau Isale, Mt. Muhi, 31 Jul 1955, 3045 m, Kinet 90 (BR) ; sine loc., Mar 1932, Scaetta 1404 (BR) .

Note. – The specimens from the Ruwenzori Mountains in Uganda cited by Grey-Wilson (1982) probably belong to a different taxon, and are excluded here.

Figures

Fig. 3. Distribution map of the two bird-pollinated species from the Impatiens purpureoviolacea complex.

Fig. 18. Impatiens superglabra. A & E, Detail of habit; B, D & F, Flower, lateral view; C, Flower, frontal view. — A–F, Fischer 9765, Democratic Republic of the Congo, Kahuzi-Biéga National Park, Mt. Kahuzi.