Rungia daklakensis (Acanthaceae), a new species from Vietnam

Rungia (Acanthaceae) contains approximately 50 species, mainly distributed in the tropical and subtropical regions of the Old World (Mabberley 2008, Hu et al. 2011). In Vietnam, it is represented by 11 species (Hai & Huyen 2009, Hai et al. 2012, Hai & Klioi 2015). During a recent floristic survey in Dak Lak Province, a distinct Rungia species was collected from the secondary forest areas of Khue Ngoc Dien Commune. After critical examination of type materials and comparison with morphologically similar taxa using relevant literature (Valeton 1908, Gagnepain 1935, Benoist 1935, Hansen 1989, Ho 2000, Hu 2002, Hai & Huyen 2009, Hu et al. 2011), we concluded that this plant represented an undescribed species. Morphologically it is closely related to R. pierrei, from which it can however be easily distinguished by the characters of spikes, fruits, etc.

Holotype

Vietnam. Dak Lak Province, Krong Bong District, Khue Ngoc Dien Commune, 12°28'25.3"N, 108°21'06.9"E, 910 m a.s.l., 17 December 2012 T.T.P. Anh, N.T. Cuong, D.V. Hai, D.T. Xifyen TN3/07-31 (holotype HN; isotype IB SC).

Paratypes: Vietnam. Dak Lak Province, Krong Bong District, Kliue Ngoc Dien Commune, 12°28'33.6"N, 108°20'26.8"E, 857 m a.s.l., 28 February 2011 T.T. Bach, D.V. Hai, BM. Quang, HM. Tam, S.D. T/iuong PTV 667 (HN!); Dak Lak Province, Krong Bong District, Kliue Ngoc Dien, 12°28'25.3"N, 108°21'06.9"E, 910 m a.s.l., 17 December 2012 T.T.P. Anh, N.T. Cuong, D.V. Hai, D.T. Xifyen, HTV10 (HN!).

Etymology

The species is named after the type locality, Dak Lak Province in Vietnam.

Habitat

Rungia daklakensis grows 111 shady places 111 secondary forest 111 association with Clinacanthus nutans, GlocJiidion sphaerogynwn, Itea ripario, Mela stoma septemnervium, Pteris cadieri and Lithocarpus sp. at 850-950 m a.s.l. During our investigation, we found only few scattered populations.