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 lutzmannii Eb.Fisch., Abrah., Holstein & S.B.Janssens, sp. nov. – Holotype : Burundi . Bururi Forest Reserve , 2180 m , 16 Mar 2012 , E. Fischer 13002 (BR barcode BR0000014532139 !; isotypes : BONN !, KOBL !) . Diagnosis. – Impatiens lutzmannii belongs to the group with hairy ovary. It differs from I. purpureoviolacea in the upper margin of the upper lateral petals being straight, while lower margin on top largely overlapping with lower lateral petals, the purple maculae on lateral united petals near throat rather small, spot-like, the beige pubescent fruit, the lanceolate leaf lamina with (25) 27–39 pairs of extrafloral nectaries at margin, and the petiole with 3–7 pairs of extrafloral nectaries. Fig. 9. Impatiens lutzmannii . A , Habit; B , Flower, frontal view; C & D , Flower, lateral view. — A–D, Fischer 13002 , Burundi, Bururi Forest Reserve. Description. – Plants ascending to erect, usually densely pubescent on stems and lower surface of young leaves, stems 20–25 cm long. Leaves with 3–18 mm long petiole, (3) 4–7 pairs of extrafloral nectaries, lamina lanceolate, 35–98.5 × 13.5–32.5 mm, margin with (25) 27–39 pairs of extrafloral nectaries. Inflorescence with 2–4 flowers, peduncle 7–21 mm long, pedicel 9–14 mm long. Flowers pink, petal base barely yellow, purple maculae at base small, ± hidden in throat. Lateral sepals (4) 6–8 × 2–2.7 mm. Lower sepal navicular, 8–11 mm long and 4–5.5 mm deep, abruptly constricted into a spiraled, usually filiform spur, spur 8–14.5 mm long. Dorsal petal 7–12.5 × 11.5–13 mm. Lateral united petals up to 28 mm long, upper margin of the upper lateral petals straight, while lower margin on top largely overlapping with lower lateral petals; purple maculae near throat rather small, spot-like, upper lateral petal 10–12 × 5.5–6.5 mm, lower lateral petal 16–21 × 6.5– 9 mm. Ovary beige-pubescent, 4–6 mm long. Fruit beige pubescent 13–15 × 6–7 mm. Figures 2 , 4C,D , 9 , 11F–I . Ecology. – Montane forest at 2180 m. Distribution. – Burundi, only known from Bururi Forest Reserve. Etymology. – Named after Nicola Lutzmann, who first discovered the species.