Gerbera serpenticola (Asteraceae: Mutisieae) – a new serpentine endemic species from Mpumalanga, South Africa

Specimens of a distinct Gerbera (Asteraceae) species were collected from ultramafic soils in Mpumalanga, South Africa. It has previously been misidentified as G. jamesonii but is clearly distinguished by several floral, vegetative and ecological features . It is smaller in stature, possessing shorter petioles and smaller leaf blades that are lanceolate to ovate and pinnately-lobed, not runcinately pinnatifid to sometimes runcinately sinuate as is characteristic of G. jamesonii. The leaves, scapes and involucral bracts are softly pilose and sometimes pubescent together with burgundy-coloured clavate glands in varying densities. Glandular hairs are absent from G. jamesonii. All florets are smaller, bright yellow (rarely whitish beige), with shorter ray florets than those of G. jamesonii. The ray florets also differ in orientation. When fresh, the ray florets are erect to suberect resulting in a more cupped appearance in the new species, whereas in Gerbera jamesonii the ray florets are patent to horizontally spreading producing a flattened, radiate appearance. This new taxon appears to be endemic to ultramafic soils unlike the ecological generalist, G. jamesonii. The differences are sufficient to recognise a new species that has so far only been found in a restricted geographical and altitudinal range north of Barberton. It is named Gerbera serpenticola D.Oosthuizen & K.Balkwill in reference to the substrate. A provisional conservation status of Critically Endangered is recommended.