Tuesday, March 27, 2018

[Botany • 2018] Dioscorea hurteri • A Threatened New Species of Dioscorea (Dioscoreaceae) from KwaZulu-Natal, South Africa


Dioscorea hurteri  R. Hills & Wilkin

in Hills, Muasya, Maurin & Wilkin, 2018. 

Summary
Morphological character data are used to show that a distinct morphotype of Dioscorea L. from KwaZulu-Natal in South Africa is an undescribed species, related to the D. buchananii Benth. species complex but differing in its inflorescence and floral morphology from all other taxa. It is described as Dioscorea hurteri R. Hills & Wilkin, illustrated and a distribution map and ecological information provided. It is known from four localities, just two of which may be protected, within a heavily developed region of South Africa and with an extent of occurrence (EOO) of 9,872 km2. Thus, its provisional IUCN conservation status is vulnerable (VU).

Key Words: Conservation, distribution, morphology, vulnerable, yam 


Fig. 2. The male plant of Dioscorea hurteri. A leaf form and a pendent inflorescence, at Ngome c. 2002. B stem pigmentation, short, dense inflorescences and more or less globose buds and flowers at anthesis showing purple tepals and a darker torus and pistillode, the former with three white nectariferous depressions per flower. C habit and inflorescences; the thicker leaf in the centre of the image is Dioscorea cotinifolia Kunth, upon which D. hurteri was climbing (B & C 9 Dec. 2017 at Botha’s Hill West of Durban).
PHOTOS: A GARETH CHITTENDEN; B & C NEIL CROUCH. 

Dioscorea hurteri R. Hills & Wilkin sp. nov. 

RECOGNITION. Dioscorea hurteri can be recognised through its dense, short, male inflorescences bearing dark purple flowers that are borne on 0.2 – 0.9 mm long pedicels, (sub)globose in bud and concealing the inflorescence axis towards its apex (see Figs 1, 2). Female plants have 3 subfree, apically recurved styles (Fig. 1G). Both male and female flowers possess nectariferous depressions in the torus that are unique in being 0.8 – 1.2 × 0.4 – 0.7 mm and reniform to cordate in outline (Fig. 1D, F, H, J). They also appear to be white in fresh material in contrast to the very dark purple torus and pistillode.

ETYMOLOGY. Named for Johan Hurter, who inspired many people to study South African Dioscorea, including the last author.


Ryan Hills, A. Muthama Muasya, Olivier Maurin and Paul Wilkin. 2018.  A Threatened New Species of Dioscorea from KwaZulu-Natal, South Africa, Dioscorea hurteri (Dioscoreaceae). Kew Bulletin. 73(1);  DOI: 10.1007/s12225-018-9742-9

2 comments:

  1. Thank you for posting this article. It looks like a small reptile could use this to hide from predators. Great photos also of the plant.
    World of Animals

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