Reynoldsia (plant)

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Reynoldsia was once a small group of shrubs and trees in the ivy family (Araliaceae) that lived on dry, leeward Pacific islands. It included eight species from Samoa, Tahiti, the Marquesas, and Hawaii.

In 2010, DNA studies showed Reynoldsia did not form a single, closely related group; it was polyphyletic, meaning it contained two different lineages. A companion paper then merged three of the species with others, leaving five Reynoldsia species.

Today, all species that were once Reynoldsia are placed in Polyscias, specifically in Polyscias subgenus Tetraplasandra, a branch of the large Polyscias group that includes many species across Malesia and the Pacific.

Reynoldsia plants were shrubs to medium-sized trees that often grew in dry habitats. They have imparipinnate (compound) leaves that are alternate on the stem, and their leaf margins are toothed rather than completely smooth. They can be told apart from close relatives by toothed leaflets, more ovary cells, and fewer stamens.

The genus Reynoldsia was created in 1854 by Asa Gray and named after Jeremiah Reynolds, a plant collector. Gray described R. pleiosperma from Samoa and R. sandwicensis from Hawaii as the first species. Over the years, Tahitian and other Samoan species were named, and there was debate about how many species truly existed, especially in Hawaii and the Society Islands.

In 2003, eight Reynoldsia species were listed in a checklist. By 2010, that number was reduced to five, and these species were moved into Polyscias as P. lanutoensis, P. pleiosperma, P. marchionensis, P. verrucosa, and P. sandwicensis.

In short, Reynoldsia is no longer recognized as a separate genus. Its former species are now part of Polyscias subgenus Tetraplasandra.