Dinteracanthus kaokoanus
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Image 1
Habit
25 Mar 2020
Image 2
Flower and leaves
25 Mar 2020
Image 3
Flower and leaves
25 Mar 2020
Image 4
Flower
25 Mar 2020
Image 5
Flower
25 Mar 2020
| Family: | Acanthaceae |
| Full name: | Dinteracanthus kaokoanus (E. Tripp & K. G. Dexter) E. Tripp & I. Darbysh. |
| ID status: | Fairly certain |
| Afrikaans common name(s): | - |
| English common name(s): | - |
| Synonym(s): | Ruellia kaokoana E. Tripp & K. G. Dexter (2012) =Dinteracanthus marlothii (Engl.) Schinz =Ruellia marlothii Engl. (1889) =Dinteracanthus velutinus C.B. Clarke =Ruellia velutina (C.B. Clarke) E. Phillips Ruellia kaokoensis van Jaarsv. |
| Status: | Native |
| Description: | Corollas purple, drying white to blue (especially towards lobe tips) with yellow markings in throat Prostrate habit Strongly pungent and produce odors reminiscent of citronella. (from Taxonomic Novelties in Namibian Ruellia (Acanthaceae), Tripp and Dexter, Systematic Botany (2012), 37(4): pp. 1023–1030) Ruellia kaokoana: Similar to R. diversifolia but differs by its larger, purple flowers. Like R. marlothii and R. acetabula but differs from both by its prostrate habit, smaller flowers, and purple corollas. Shrubs to 0.3 m, woody, sprawling and prostrate against substrates, the younger stems subquadrangular, densely pubescent with eglandular trichomes of varying lengths, the older stems terete, less densely pubescent with eglandular trichomes and becoming glabrous towards proximal portions of plants with conspicuous cystoliths, the internodes of young stems mostly < 1 cm long, congested and obscured, the internodes of older stems to 4 cm long. Leaves with petioles to 4 mm long, the petioles pubescent like young stems, the blades ovate to rounded, 1.0–2.5 x 0.8–1.9 cm, 0.9–1.8 times longer than wide, acute to obtuse to rounded apically, rounded to acute basally, the margins entire, the adaxial and abaxial surfaces pubescent or, more frequently, tomentose, trichomes eglandular, cystoliths and sessile patelliform glands present but inconspicuous, glands drying pale yellow to dark red. Inflorescences of congested simple or compound dichasia in axils of leaf-bearing nodes. Bracts foliaceous, dense, both first and second order bracts like leaf blades in shape, pubescence, and glandularity but becoming reduced in size towards distal portions of inflorescences. Flowers on pedicels to 1 mm long. Calyces strongly zygomorphic, the lobes free to the receptacle, the dorsalmost lobe the largest (ca. 1.5–2 x 0.3–0.8 cm, elliptical), the two ventral lobes intermediate (ca. 1.3–1.7 x 0.1– 0.3 cm, oblanceolate), and the two lateral lobes the smallest (ca. 1.1–1.7 x < 1 mm, linear), the dorsalmost lobe with conspicuous marginal, brochidodromus collecting veins, all lobes together with first and second order bracts drying pale yellowish brown during fruiting stages. Corollas purple, drying white to blue (especially towards lobe tips) with yellow markings in throat, infundibular, 2.8–3.1 cm long, the narrow unexpanded portions 13–16 x 2.5 mm, the expanded portions 1–1.8 x 0.8–1.0 cm, the lobes ca. 4 x 2.5 mm, rounded to emarginate apically. Stamens included within corolla tube, didynamous, the filaments 2.5–2.9 cm long (longer pair) or 2.1–2.3 cm long (shorter pair), the free portions of filaments 7 mm (longer pair) and 5 mm (shorter pair), the fused filament sheath (curtain) enclosing 3/4 of unexpanded portion of tube; anthers bithecous, 3–3.5 mm long, mucronate basally. Styles ca. 2.5–2.9 cm long, with short ascending eglandular trichomes, included within corolla tube. Stigmas bifid but dorsal lobe completely reduced, anterior lobe ca. 2.5–3 mm long. Capsules (only two seen) ca. 12–13.5 mm long, elliptical. Seeds 1.25 mm long, discoid, ca. 16–18 per capsule, covered by mucilaginous hygroscopic trichomes. Etymology—The specific epithet refers to the region in which this plant was discovered by the authors, the Kaokoveld or Kaokoland of northwestern Namibia (Kunene Region), a region of tremendous geological and botanical diversity. (from Taxonomic Novelties in Namibian Ruellia (Acanthaceae), Tripp and Dexter, Systematic Botany (2012), 37(4): pp. 1023–1030) The main features distinguishing R. kaokoana from R. diversifolia are its purple (vs. white) flowers and its larger corollas (ca. 26–31mm [12–16mm for narrow unexpanded portion] vs. 23–24 mm [8.5–10 mm for narrow unexpanded portion] in R. diversifolia). We are not aware of any collections of R. diversifolia with anything other than white flowers, but in putatively closely related species, e.g. R. marlothii, floral color variants are known. (from Taxonomic Novelties in Namibian Ruellia (Acanthaceae), Tripp and Dexter, Systematic Botany (2012), 37(4): pp. 1023–1030) Ruellia kaokoana is also similar to the Namibian species R. marlothii and R. acetabula but is easily differentiated from both by its smaller, differently shaped corollas that are purple instead of red, yellow, or white, and by its distinctly prostrate growth form. (from Taxonomic Novelties in Namibian Ruellia (Acanthaceae), Tripp and Dexter, Systematic Botany (2012), 37(4): pp. 1023–1030) |
| Link(s) |
African Plant Database
JSTOR Plant Science Kew Herbarium Catalogue BGBM Berlin-Dahlem - Virtual Herbarium Züricher Herbarien iNaturalist (Namibia / Alex Dreyer) iNaturalist (Namibia) iNaturalist (southern Africa) Flora of Zimbabwe Fleurs de notre Terre - Galerie Namibie Tree Atlas of Namibia |
| Content last updated: | 18 Apr 2024 |
