Introducing Opilia – a sister to the mistletoes and sandlewood
Opiliaceae is a small family of 39 species related to the mistletoe (Loranthaceae) and sandlewood (Santalaceae) families. They are all parasitic to some degree on other plants. Melientha suavis (phak waan paa) and Champereia manillana (false olive, chemperai) are cultivated as vegetables in Thailand, Vietnam, Laos, and Cambodia. Urobotrya siamensis and Lepionurus sylvestris (lin wei mu shu) are used as local medicines in Thailand and Malaysia (Hiepko, 2008).
Many of the genera and species have reduced floral parts, making interpretation of relationships challenging. New molecular data are enabling these relationships to be re-defined (Nickrent et al. 2010).
Australia has only five species in the Opiliaceae, and three of these are only recently included as the genus Anthobolus (desert broombush) has traditionally been placed in the Santalaceae (Kuijt 2015). The Australian species are in tropical or in arid habitats, including Opilia amentacea (fragrant opilia; left and centre photos below) and Cansjera leptostachya (miliba; right-hand photo).
Research lead by Che-Toan Le and Bing Liu, in collaboration with Li-Min Lu and Zhi-Duan Chen at the Chinese Academy of Sciences in Beijing, Jun Wen at the Smithsonian Institution in Washington, and Russell Barrett at the Royal Botanic Gardens, Sydney, has been published in the Journal of Systematics and Evolution. This research has shown that Anthobolus is related to Agonandra (palo verde), and shares several morphological characteristics with other Opiliaceae, supporting its inclusion in the family.
Recognition of the Chinese endemic genus Yunnanopilia (jing hua shan you) is supported. The paper proposes recognition of four tribes within Opiliaceae with the description of a new tribe, Champereieae to include the genera Champereia, Melientha and Yunnanopilia.
Hiepko P. 2008. Opiliaceae. In: Anderson CE, Marhold K eds. Species Plantarum: Flora of the World. Genève: Conservatoire et Jardin botaniques de la Ville de Genève. 12: 1–71.
Kuijt J. 2015. Santalales. In: Kuijt J, Hansen B eds. The families and genera of vascular plants. Flowering plants: Eudicots; Santalales, Balanophorales. Cham: Springer. 12: 2–189.
Le, C.-T., Liu, B., Barrett, R.L., Lu, L.-M., Wen, J. & Chen, Z.-D. 2018. Phylogeny and a new tribal classification of Opiliaceae based on molecular and morphological evidence. Journal of Systematics and Evolution 56(1): 56–66. doi:10.111/jse.12295
Nickrent DL, Malécot V, Vidal-Russell R, Der JP. 2010. A revised classification of Santalales. Taxon 59: 538–558.