Two new species of Stylochaeton (Araceae: Aroideae) from South Africa

Abstract

We are describing here Stylochaeton glaucophyllum and S. sekhukhuniense, two new species from northeastern South Africa. Both species have a restricted distribution and are endemic to the Sekhukhuneland Centre of Plant Endemism, Limpopo and Mpumalanga Provinces, South Africa. The new species occur sympatrically with S. natalense, but never with one another. Stylochaeton glaucophyllum prefers norite and pyroxenite hills and mountains, whereas S. sekhukhuniense is associated with similar rock types in low-lying rocky areas. Both new species have the base of the spadix and infructescence partly below-ground and are mainly associated with open savannah. Stylochaeton glaucophyllum can be distinguished from S. sekhukhuniense in having greenish blue leaves with linear lobes while S. sekhukhuniense has green leaves with elliptic lobes. The leaves of S. glaucophyllum are longer (112–332 mm) than those of S. sekhukhuniense (44–180 mm). The petiolar sheath of S. sekhukhuniense extends into two slender, curling ligulae which are absent in S. glaucophyllum. Also included here is a key to the seven currently accepted species of Stylochaeton in southern Africa (South Africa, Eswatini, Zimbabwe and Mozambique).