A yellow flower on a limestone wall in Khon Kaen

On a karst outcrop in Phu Pha Man District, botanist Thawatphong Boonma and his colleagues found a ginger relative that grows nowhere else they know of. They named it Boesenbergia calcicola — the limestone dweller. It is the second such plant the team has described from these rocks in six weeks.

What set it apart was small and precise. The inflorescence stood conspicuously exserted where its closest relative, B. petiolata, keeps its own tucked away. The bracts were shorter. The flowers measured 2.0 to 2.5 centimetres across, and the labellum — the lip petal that in gingers does the work of attracting insects — carried a pattern no one had recorded before.

Boonma published the description with Surapon Saensouk, Piyaporn Saensouk, Mukdamas Ruengrit, Pathomthat Srisuk, Prasert Ruannakarn and Min Khant Naing in the journal Life. The name comes from the Latin calx, lime, and -cola, dweller. It is a plain name for a plant that has been found on exactly one rock.

That is also the problem. Because the species is known from a single outcrop and nothing else about its range has been established, the authors listed it as Data Deficient — the conservation category that means: we do not yet know enough to say whether this is in trouble.

The three lead authors work from the Walai Rukhavej Botanical Research Institute at Mahasarakham University, and they have been at this rhythm for a while. Six weeks before calcicola, they described B. lamudiae from Nong Hin District in neighbouring Loei Province, at roughly 425 metres, on limestone again. Boonma's earlier work includes three Curcuma species, the turmeric genus.

The genus they are adding to was erected in 1891 by the German botanist Otto Kuntze, and it holds a plant most Thai kitchens know: Boesenbergia rotunda, krachai, the yellow fingerroot rhizome sold fresh in markets and pounded into curry paste.

Karsts behave like islands. Each outcrop is its own weather, its own soil chemistry, its own isolation, and over long spans of time that isolation produces plants found on one hill and no other. It also makes them easy to lose. The same rock that shelters a species is quarry stone, and field botanists working these hills say the pressure is rising.

Which gives the naming its quiet urgency. A plant without a name cannot be listed, cannot be protected, cannot be missed. Boonma and his colleagues have given this one a name and an address, and little else is known about it yet.