Evolution of Impatiens (Balsaminaceae) in the Albertine Rift – The endemic Impatiens purpureoviolacea complex consists of ten species Author Fischer, Eberhard 0000-0001-7455-9833 Stefan Abrahamczyk, & Institut für Integrierte Naturwissenschaften - Biologie, Universität Koblenz-Landau, Universitätsstrasse & 56070 Koblenz, Germany efischer@uni-koblenz.de Author Abrahamczyk, Stefan 0000-0001-8047-932X Norbert Holstein & Nees Institute for Biodiversity of Plants, University of Bonn, Meckenheimer Allee 170, 53115 Bonn, Germany sabraham@uni-bonn.de Author Holstein, Norbert 0000-0001-9892-0355 & Steven B. Janssens & Natural History Museum, Cromwell Rd., London SW n.holstein@nhm.ac.uk Author Janssens, Steven B. Botanic Garden Meise, Nieuwelaan 38, Meise, 1860, Belgium steven.janssens@plantentuinmeise.be text TAXON 2021 2021-09-06 70 6 1273 1299 http://dx.doi.org/10.1002/tax.12566 journal article 10.1002/tax.12566 495154d8-5ca2-4a89-8b30-574f579034cb 1996-8175 5849572 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. Fig. 12. Impatiens ludewigii . A & C , Habit; B , Flowers (left, middle), right a flower of Impatiens purpureoviolacea ; D , Flower, frontal view; E , Flower, lateral view. — A & C, Fischer 14500 , Rwanda, Uwinka. B, D & E, Fischer 13914 , Rwanda, Gisovu. Etymology. – Named after Elwira Urzula Schweizer, who supported the work of the first author.