Introduction

Containing a single genus, the relationships of this family have been very difficult to decipher based on morphology, and it has formerly been included in several other families. Hooker (1887) initially included it (with reservations) in Euphorbiaceae, and it was later considered an outlying branch of Celastraceae before being moved to Icacinaceae. Simmons and Hedin (1999) restored the genus to Euphorbiaceae on morphological grounds before molecular phylogenetic studies robustly rejected this placement.

Further analyses have indicated that Lophopyxis has no close relatives, which is why it was so hard to place. Savolainen et al. (2000) moved the family into the order Malpighiales based on chloroplast rbcL sequences, where it was sister to Microdesmis (Pandaceae) in their analysis. Davis et al. (2005) indicated that it is sister to Drypetes, one of two genera in the similarly obscure Putranjivaceae; however, the relationship is not a recent one as the analysis indicates that they have been separated by about 90 million years. The sister relationship between Lophopyxidaceae and Putranjivaceae is also supported by Wurdack et al. (2004), Tokuoka and Tobe (2006), Soltis et al. (2011), Xi et al. (2012), Cai et al. (2020) and Jin et al. (2020).


References and Further Reading

Hooker JD (1887) Icones Plantarum. 18. London: Williams and Norgate.

Jin DM, Wicke S, Gan L, Yang JB, Jin JJ, Yi TS (2020) The loss of the inverted repeat in the Putranjivoid Clade of Malpighiales. Frontiers in Plant Science 11(942). https://doi.org/10.3389/fpls.2020.00942

Simmons MP, Hedin JP (1999) Relationships and morphological character change among genera of Celastraceae sensu lato (including Hippocrateaceae). Annals of the Missouri Botanical Garden 86(3): 723-757. https://doi.org/10.2307/2666152

Soltis DE, Smith SA, Cellinese N, Wurdack KJ, Tank DC, Brockington SF, Refulio-Rodriguez N.F, Walker JB, Moore MJ, Carlsward BS, et al. (2011) Angiosperm phylogeny: 17 genes, 640 taxa. American Journal of Botany 98(4): 704-730. https://doi.org/10.3732/ajb.1000404

Tesh JP (2012) A survey of floral structure in Drypetes Vahl (Putranjivaceae) and related genera. Masters Thesis: The University of Edinburgh, Edinburgh, Scotland.

Tokuoka T, Tobe H (2006) Phylogenetic analyses of Malpighiales using plastid and nuclear DNA sequences, with particular reference to the embryology of Euphorbiaceae sens. str. Journal of Plant Research 119: 599-616. https://doi.org/10.1007/s10265-006-0025-4

Wurdack KJ, Hoffmann P, Samuel R, de Bruijn A, van der Bank M, Chase, MW (2004) Molecular phylogenetic analysis of Phyllanthaceae (Phyllanthoideae pro parte, Euphorbiaceae sensu lato) using plastid RBCL DNA sequences. American Journal of Botany 91(11): 1882-1900. https://doi.org/10.3732/ajb.91.11.1882