Ochna species new to science discovered in the Barberton Mountains

The new Ochna species, Ochna barbertonensis in its grassland habitat. Photo: D. Oosthuizen

Botanists have discovered a new species of Ochna in the grasslands of the Barberton Mountains. The species was first collected in Songimvelo Nature Reserve in 2012. In 2013 and 2017, additional collections were made in Mountainlands Nature Reserve and next to a road in a pine plantation.

The species was scientifically described by Toral Shah and Iain Darbyshire, both from the Royal Botanic Gardens, Kew and John Burrows from the Buffelskloof Herbarium in Mpumalanga. The paper was published in the journal Phytotaxa on 7 November 2018. The species was given the scientific name Ochna barbertonensis after the Barberton Centre of Endemism to which it is restricted.

The black, mature fruit. Photo: D. Oosthuizen

About 85 species of Ochna are known to science and include trees, shrubs and shrublets. They are also known as “Mickey Mouse Plants” due to “the enlarged, persistent sepals becoming red in fruit with black drupes sitting on an accrescent red receptacle”. According to the authors “throughout Africa many Ochna species have highly restricted ranges.” These species are of high conservation concern due to habitat loss. Many endemic species are known from only a few collections and occupy very specific habitats. “Therefore, understanding and documenting these species is highly important for their protection and in turn the protection of their habitat.”

Ochna barbertonensis was found growing in short Barberton Montane Grassland on reddish clay-loams at an elevation of 1104 – 1320 meters.

John Burrows attempted to identify the initial specimen and at first considered it to be a form of Ochna confusa due to its suffrutescent habit and distribution in the same region. However, further collections, investigations and comparisons showed distinct morphological differences. The new species was also compared to Ochna natalitia, which is potentially more closely related but a big difference is that Ochna natalitia is a tree up to 10m tall and Ochna barbertonensis is a dwarf suffrutex up to 20 cm tall.

Yellow flower showing the orange anthers with open pores. Photo: D. Oosthuizen

As for the conservation status the new species occurs within well protected nature reserves and occupies an area of 16 km².  “It is only known from five collections with an extent of occurrence of 34 km² making it a ‘Rare’ species under the Red list of South African Plants.” Both reserves are in the newly designated World Heritage Site recognised for the scientifically important Barberton Greenstone Belt geological formation.

Reference: Shah,T., Burrows, J. & Darbyshire, I. (2018) A new species of Ochna (Ochnaceae) from the Barberton Mountains of Mpumalanga, South Africa. Phytotaxa 374 (3):241-248.

http://dx.doi.org/10.11646/phytotaxa.374.3.5

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