Spathiostemon moniliformis

The species grows as a shrub or tree, in height up to 10m, with a trunk diameter at breast height up to 11 cm.[1][2] Leaves are rarely ovate tending usually to elliptic, some 6.2-26.5 x 2.3-9.5 cm in size, on both sides they are smooth and glabrous. Flowers are white to yellowish. The fruit is reddish to dark brown, smooth and glabrous, some 9 x 6mm in size. It flowers and fruits from December to March, August to September.

The species is distinguished from its sister taxa Spathiostemon javensis by the following traits: Glabrous petioles; the leaves do not have domatia; the inflorescences are glabrous, and the staminate inflorescences are from 6 to 28 cm long; the pistillate flowers have sepals in 2 whorls of 3; the ovary and fruit are smooth.[1]

The taxa is distinguished from other Euphorbiaceae growing in Thailand by having: elliptic leaves whose basal margin has 3 black dot-like glands on either side of the midrib; the petioles are both basally and apically pulvinate; seeds do not have arilloid.[3]

The shrub/tree is common in evergreen forest and in secondary forests that have evergreen patches.[1] It grows from 10 to 200m altitude.

The tree is endemic to southern/peninsular Thailand.[4][1]

Kha khao and khan laen are names used for this species in Surat Thani Province, Thailand.[1]

The English botanist Herbert Kenneth Airy Shaw, who worked extensively on tropical Asian botany and entomology, described the species in 1962, in the Kew Bulletin.[5]

• Govaerts, R., Frodin, D.G. & Radcliffe-Smith, A. (2000). World Checklist and Bibliography of Euphorbiaceae (and Pandaceae) 1-4: 1–1622. The Board of Trustees of the Royal Botanic Gardens, Kew.
• van Welzen, P.C. & Chayamarit, K. (2007). Flora of Thailand 8(2): 305–592. The Forest Herbarium, National Park, Wildlife and Plant Conservation Department, Bangkok.