What’s in a name?

DNA technology is changing the way plants—and especially orchids—are named, as the cases of Orthochilus aculeatus subsp. aculeatus and subsp. huttonii demonstrate.

By Gerrit van Ede

In the botanical world, name changes occur reasonably frequently due to a number of rules that specify how a plant should be named. Lately, new technology utilising DNA research to establish the relationship between different species is also causing names to be revised in line with new scientific understanding.

One of the long-standing rules that has profoundly affected the naming of plants, especially orchids, is that the oldest name is the one that should be used. Therefore, if somebody finds an older description of the species with another name than the one currently used, the older name must be used.

With the advent of easier DNA analysis, botanists have begun to determine the genetic make-up of many species. This new technology is causing big changes in plant nomenclature as DNA analyses are able to show just how closely various species are related—or, indeed, how distant they are.

This scenario played out with what used to be called Eulophia aculeata subsp. huttonii and Eulophia huttonii. Following DNA analysis, these plants were moved into the Orthochilus genus, and were thus renamed Orthochilus aculeatus subsp. huttonii and Orthochilus aculeatus subsp. aculeatus.

Orthochilus aculeatus subsp. huttonii bears striking flowers standing proud of the short grass of November (Photograph: Gerrit van Ede)

The genus Orthochilus contains at least 34 species, mostly native to Africa and Madagascar. A few species exist in Central and South America. It was first described in 1850 by Achille Richard, a French botanist.

From these earliest days, it was recognised that Orthochilus shares many characteristics with the larger genus Eulophia, and the two were often used interchangeably. However, DNA analysis published in 2014 indicated that Orthochilus had to be recognised as a separate genus, and that some species would have to be reassigned from Eulophia to Orthochilus.

The species in the Orthochilus genus can be distinguished from the species in the genus Eulophia by the fact that their petal and sepals are similar in shape, size and colour, while Eulophia species mostly have sepals and petals that differ in appearance. Orthochilus’ flowers also tend to be bell-shaped (campanulate) and downward-facing.

Many plants are named after noticeable characterises of the plant or flower. Eulophia refers to the well-developed crests or hairs visible on the lip of most species,[1] whereas Orthochilus refers to a straight or upright lip.[2] Aculeatus in Latin means spine-like or prickly, referring most likely to the stiff upright sharp-pointed leaves of these plants.[3]

Other plants are named after the collector or botanist describing the plant or where the plant was found. In this case huttonii refers to the discoverer of the type specimen, Henry Hutton (1825 – 1896), who collected for the James Vietch company, a famous nursery company based in the United Kingdom.

Orthochilus aculeatus subsp. huttonii is one of the early flowering orchids at Verloren Valei. At flowering time, mainly during November, the surrounding grassveld is still short and the large flowers (24 – 30mm across), in many cases of striking colours, stand above the grass and can be easily spotted.

Orthochilus aculeatus subsp. huttonii, showing the downward-facing bell-shaped flowers characteristic of the genus (Photograph: Gerrit van Ede)

O. aculeatus subsp. huttonii is not common on the Reserve. They tend to occur in small colonies and if you find one, have a look around because there could be some more plants in the vicinity. It occurs only in South Africa.

The other subspecies, aculeatus, also occurs on Verloren Valei. By contrast, though, flowers later and, because it is smaller, is much more difficult to find. We found this subspecies before we found the more striking subspecies huttonii. This orchid is found also in Lesotho and Swaziland, and also occurs in the winter rainfall area of South Africa.

The flowers of both subspecies vary quite a lot in colour from white to pinkish to mauve.

[1] Eu, = well; (well, good, thoroughly, completely, truly) lophos, = crest, tuft of hair; a cock’s comb. (refers to crests on the lip), see www.plantnames.co.za.

[2] Orthos, = straight; (in height), upright, standing erect; (in line), a straght line; cheilos¸= a lip, see www.plantnames.co.za.

[3] Acus, = a needle or pin; as being pointed; -ulus, = diminutive; aculeus, = a sting; of plants, a spine or prickle; -atus, = indicates possession or likeness. aculeatus, = furnished with stings or prickles, thorny, prickly. (prickly, spine-like) (the lip is aculeate, the prickles referred to being the slender papillae on the centre of the midlobe), see www.plantnames.co.za.