A new species of Jasminum ( Oleaceae ) from Thailand

In revising the distribution and conservation status of Jasminum in Thailand, a new species, Jasminum bhumibolianum Chalermglin, was discovered in NE Thailand. It is described and illustrated and its conservation status is assessed as Critically Endangered.


INTRODUCTION
The genus Jasminum in Thailand was revised by Kerr (1939) and Green (2000), the latter included 31 species of which two, J. decipiens P.S.Green and J. perissanthum P.S.Green, were described as new species (Green 1995).Since then J. rufohirtum Gagnep.was reported as a new record for Thailand (Srisanga et al. 2004).
Thailand Institute of Scientific and Technological Research (TISTR) is involved in a project to study the distribution and conservation of rare and endangered species as part of the Plant Genetic Conservation Project initiated by HRH Princess Maha Chakri Sirindhorne.Focus on the genus by the first author led to the discovery of this new species on a karst limestone hill in north-eastern Thailand.In comparing it with native species from neighbouring countries, such as Malaysia (Kiew 1994a, b), China (Chen et al. 1996) and Vietnam (Tran 2003), it proved to be a new species most similar to J. extensum Wall.ex G.Don and J. pierreanum Gagnep. in its unifoliolate, elliptic leaves with lateral veins where the basal vein is not more prominent than the others.However, the new species differs from both in its longer calyx lobes 3 -4 mm long (vs 0.25 -1 mm long), its shorter corolla tube 12 -15 mm long (vs 15 -22 mm long) and its 3 -4 mm wide corolla lobes (vs 1-2 mm wide) and its larger, unlobed fruit (only one of the two lobes develops) and is ellipsoid, c. 11 by 9 mm (vs globose and 5 -6 mm diam).Unlike the other two species, which are primarily species of evergreen forest, this new species is restricted to karst limestone.In addition, it is very different from other Thai jasmine species in its short, hard, triangular calyx lobes that are almost spine-like and in its 1-lobed fruit that when ripe detaches together with its pedicel and calyx.Chalermglin, Similar to Jasminum extensum and J. pierreanum in its leaves, J. bhumibolianum is different from them in its calyx lobes 3 -4 mm long (not 0.25 -1 mm long), its short corolla 12-15 mm long (not 15 -22 mm long) and its broader corolla lobes 3-4 mm wide (not 1-2 mm wide).
Etymology.The species is dedicated to His Majesty King Bhumibol Adulyadej on his 84th anniversary in recognition of the great efforts he has made to conserve native plants in Thailand.
Distribution -Endemic to Loei Province, north-eastern Thailand.Known only from the type locality.
Ecology -In mixed deciduous forest, growing in a gully on a karst limestone mountain.Altitude 715 m.Flowering July-September; fruiting November-January.
Vernacular name -Mali Chaloem Narin (มะลิ เฉลิ มนริ นทร์ ).Conservation status -CR B1ab(iii).This new species, endemic to Thailand, is Critically Endangered (IUCN 2001), because it is known from a single locality where only two plants were discovered and the area is not legally protected.