Two new dogbanes: Hoya ruthiae and Hoya bakoensis

Hoya bakoensis

Hoya ruthiae was named after the tropical botanist who collected the original plants, Ruth Kiew. It grows on limestone with its so far only location being Malaysia. Therefore, its conservation status is not yet known and the plant species is categorised as Data Deficient following the IUCN guidelines. However, it is widely available in cultivation.

The second new species, Hoya bakoensis, was discovered in 2015 and was named after its for now sole locality, the Bako National Park in Malaysia. The species prefers moist, shady kerangas heath forests near streams. Most often, it sprouts its seedlings in the openings of small ant nests from inside hollow tree trunks and climbs up its host tree likely in need for more light.

For our experts: Two new Hoya R.Br. species from Borneo are described and illustrated. The first, Hoya ruthiae Rodda was collected in Sabah on Bukit Baturong, a limestone outcrop. It is one of the few species in the genus to have clear exudate. It is compared with the morphologically related Hoya uncinata Teijsm. and Binn. The other, Hoya bakoensis Rodda, was collected in the kerangas forests of Bako National Park. It belongs to Hoya section Acanthostemma (Bl.) Kloppenb., a section with numerous members in the Philippines but under-represented in Borneo.