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This species is accepted, and its native range is S. Central Kenya to Tanzania.
A specimen from Kew's Herbarium

[FTEA]

Acanthaceae (part 2), Kaj Vollesen. Flora of Tropical East Africa. 2008

Type
Type: Tanzania, Masai District: Ardai Plains, Greenway 6814 (EA!, holo.; K!, PRE!, iso.)
Morphology General Habit
Much branched perennial or shrubby herb to 75 cm tall with erect to procumbent stems, sometimes rooting at lower nodes, forming dense clumps; young stems quadrangular, subglabrous to puberulous or sericeous-puberulous and with slightly longer hairs on edges, no capitate glands, eventually with exfoliating bark
Morphology Leaves
Leaves broadly elliptic-obovate to orbicular, largest 2–5 × 1.3–4.5 cm (less than twice as long as wide), apex subacute to emarginate, base attenuate, decurrent to stem or with an ill-defined petiole up to 1.5 cm long, margin subentire to dentate, subglabrous to sparsely and uniformly sericeous-puberulous; stipule-sheath 0.5–1 mm long. Flowers solitary or in 3-flowered cymules (peduncles up to 5 mm long) which are arranged in narrow racemiform axillary sericeouspuberulous panicles; bracts foliaceous, gradually smaller upwards; pedicels 0.5–2 mm long, puberulous and with subsessile glands; bracteoles linear-lanceolate to obovate, up to 7 mm long, puberulous and with slightly longer ciliae, with or without subsessile (shorter than hairs) capitate glands
Morphology Reproductive morphology Flowers Calyx
Calyx 5–8(–9 in fruit) mm long, puberulous and with scattered to dense subsessile (shorter than or same length as hairs) capitate glands, tube 4–5 mm long; teeth triangular, acute or subacute, dorsal 2.5–4 mm long, ventral 2–3 mm long with the free part 1–2 mm long
Morphology Reproductive morphology Flowers Corolla
Corolla white to pale pink or mauve with orange patches on lower lip, 13–17 mm long, sericeous-puberulent on the outside; tube 8–10 mm long of which the throat 2–4 mm; lips 4–8 mm long; lobes oblong-obovate, 2–3.5 (upper lip) to 5 (lower lip) mm wide, retuse to truncate; palate with numerous long stiff straight hairs
Morphology Reproductive morphology Flowers Androecium Stamens Filaments
Filaments 2–6 mm long, with scattered hairs and glands throughout; anthers 1.5–2 mm long, rounded, connective with sparse capitate glands
Morphology Reproductive morphology Flowers Gynoecium Stigma
Dorsal stigma lobe about half the length of ventral
Morphology Reproductive morphology Fruits
Capsule and seed not seen
Ecology
Seasonally flooded grassland on grey to black or brown clayey soils, Acacia-Commiphora bushland on clayey soil; 1050–1400 m
Note
This species occurs on the northern fringes of the widespread D. quadrangulare, and was at first thought to be merely a form of it. But there are enough differences to recognise it as a distinct species; the main difference being the absence of capitate glands and long pilose hairs from most parts. Where capitate glands occur (mainly on the calyx) they are very short. The dimensions of the calyx and corolla are at the lower end of the variation in D. quadrangulare.
Distribution
Flora districts: K4 T1 T2 T3 T5 Range: Not known elsewhere

Native to:

Kenya, Tanzania

Duosperma subquadrangulare Vollesen appears in other Kew resources:

Date Reference Identified As Barcode Type Status
Nov 1, 2008 Freidberg [K11], Tanzania K000191272
Apr 27, 2005 Greenway [6814], Tanzania K000394023 isotype

First published in Kew Bull. 61: 305 (2006)

Accepted by

  • Vollesen, K. (2008). Flora of Tropical East Africa, Acanthaceae(1): 1-285.

Literature

Flora of Tropical East Africa

  • K.B. 62: 305, fig. 4 (2006).

Flora of Tropical East Africa
Flora of Tropical East Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Herbarium Catalogue Specimens
Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

Kew Backbone Distributions
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0