New species of Arum family reported from Myanmar

The Arum family (Araceae) consists of terrestrial or aquatic shrubs, vines, or herbs. Amorphophallus is a large genus of about 200 tropical and subtropical tuberous herbs of the Arum family. Fifteen Amorphophallus species have been reported from Myanmar, five of which are known to be endemic.

A local plant enthusiast has recently found an unknown Amorphophallus species, flowering in May and June 2023 in Hpa-an District, Kayin State. He then sent the samples to a researcher in Myanmar. After meticulously examining its morphology and comparing it with protologues and relevant literature, as well as with digitized type specimens of Amorphophallus from across Myanmar and neighboring countries, researchers from the Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences and their collaborators confirmed that the collected specimens represent a new species.

The new species was named as Amorphophallus mirabilis in reference to its striking foliage. The find has been published in the Nordic Journal of Botany.

Amorphophallus mirabilis is a seasonally dormant herb. It is morphologically similar to A. dzui from northern Vietnam, but differs in having a much longer peduncle, a spathe that is pale purplish brown one the outside, light chestnut brown on the inside basal half, and densely covered with fleshy, irregularly shaped warts, the upper half yellowish green, and whole or transversely bilabiate stigmas.

Amorphophallus mirabilis is currently known only from its type locality in Hpa-an District, Kayin State, Myanmar, where it was found in the karst limestone forest growing in a crack of a moist sandstone rock under a closed to semi-open canopy of seasonal rainforest or dry evergreen forest, at an elevation of about 100 meters above sea level.

During their on-going work on the taxonomy of the Araceae family in Myanmar, the researchers also made a new record of Amorphophallus napalensis (a tuberous geophytic plant). "This is the first report of the species in Myanmar and represents an important expansion of its geographic distribution, where it was found growing along the roadsides/trails of Mt. Victoria in Myanmar," said Mark Arcebal K. Naive of XTBG.

With the discovery of the new species and A. napalensis, Myanmar now has 17 Amorphophallus species.