Taxonomy of the small south african endemic genus microdon choisy (scrophulariaceae: limoselleae)
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Date
2025
Journal Title
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Publisher
Elsevier B.V.
Abstract
The taxonomy of the genus Microdon Choisy (Scrophulariaceae: Limoselleae) is revised. It is a genus of ericoid or microphyllous shrubs separated from Selago L. and other uniovulate members in the tribe by a combination of characters, notably the calyx tube adnate for up to half its length to the bract, with the posticous ovary locule aborted. The entirely eglandular vestiture of the plants is also diagnostic. The plicate calyx is very shortly and sub-equally 5-lobed and glabrous or more usually with spinules on the lower ribs. The flowers are moderately long-tubed with lobes shorter than the tube, and the anticous stamens are shortly included with the posticous pair either exserted or lacking. The fruits are clearly adapted for wind-dispersal, the diaspores shed as a unit comprising the prominent, wing-like bract attached to the calyx that expands to partially or fully enclose the solitary coccus, which remains attached to the receptacle. We recognise seven species in the genus, segregated between sect. Microdon for four species with straight corolla tubes and four stamens with smaller anthers 0.5–1.0 mm long, and sect. Agathelpis for three species with arcuate or geniculate corolla tubes and two stamens with larger anthers ± 2 mm long. The new species M. lyperioides J.C.Manning & R.Maluleke from the Piketberg is distinguished from the sympatric M. dubius by the longer leaves, dense whitish pubescence on the stems, and the markedly patent flowers with longer corolla tube mm 3\0554 mm"?>13–14 mm long and longer corolla lobes 3–4 mm long.
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Keywords
Agathelpis, Greater cape floristic region, Nomenclature, Selagineae, Selago
Citation
Manning, J.C., Maluleke, R., Boatwright, J.S. and Magee, A.R., 2025. Taxonomy of the small South African endemic genus Microdon Choisy (Scrophulariaceae: Limoselleae). South African Journal of Botany, 177, pp.118-138.