The vernacular name for Hopea polyalthioides (Dipterocarpaceae), Giam rambai refers to drooping leaf-sprays. The leaves are large with an oblong shape (8 x 2.5 cm to 27 x 6 cm), arranged in distichous sprays on long, slender branches rather like some species of Myristicaceae (penarahan) and Anonaceae (mempisang). A leaf has well-spaced veins (about 12) with prominent reticulations on the lower surface.

Hopea polyalthioides is an under-storey tree, unlike many dipterocarps which are emergent trees above the canopy. This small-sized tree has a girth of not more than 30 cm. The 8 mm petiole is velvety when young. The leaf undersurface is velvety soft but later becomes glabrous as it ages. The flowers are pale pink and rather small (1 cm across) when expanded. The fruit is about 2 cm long, the nut is ovate with a sharp-pointed tip and embraced at the base by the sepals.

Hopea polyalthioides is endemic to Peninsular Malaysia. It is recorded in Johor from Panti Forest Reserve (FR), Gunung Arong FR, Jemaluang FR and Tenggaroh FR and in Senaling Inas, Negeri Sembilan. It inhabits lowland areas of dipterocarp forests.

Hopea polyalthioides produces a small pole and has no potential value in the timber industry. This species is threatened by land conversion activities. According to Malaysia Plant Red List (Chua et al, 2010), H. polyalthioides is categorized as Endangered (EN B2ab(iii)). Forest Research Institute Malaysia (FRIM) in collaboration with Forestry Department of Peninsular Malaysia (JPSM) is undertaking ex situ conservation through germplasm collection. Wildings and seedlings of Giam rambai are being maintained and monitored at the Kepong Botanic Gardens (KBG).