Tetraplasandra (Tetraplasandra)

Description

Tetraplasandra is an obsolete genus of flowering plants in the ivy family, Araliaceae. They are small to medium trees, (rarely shrubs or large trees) of mesic to wet forests. Some authors have recognized as many as 19 species in Tetraplasandra, while others have recognized as few as six. In 2007, the authors of a scientific paper recommended that the genus be divided into nine species. In 2010, all of these nine species were included in ''Polyscias'' subgenus Tetraplasandra, a subgenus of 21 species in the large genus Polyscias, which will comprise about 250 species, when about 90 undescribed species are published. The range of variation in Tetraplasandra is unusually large for a genus in Araliaceae Most of the species were originally described in other genera which were later merged with Tetraplasandra. The type species for the genus is T. hawaiensis. As defined by es:William R. Philipson in 1970, Tetraplasandra is endemic to Hawaii and occurs on six of the eight main islands. Ni-ihau and Kaho-olawe are low-lying and dry; consequently, they do not support Tetraplasandra. T. oahuensis, T. kavaiensis, and T. hawaiensis are found on six, five, and four of the islands, respectively. The other species are single-island endemics. T. oahuensis and T.kavaiensis have done well in cultivation in Southern California. They are sensitive to heat, but very tolerant of shade, and they need some wind protection. In horticulture, T. kavaiensis has often been misidentified as T. meiandra. True T. meiandra is now treated as a synonym of T. oahuensis. T. gymnocarpa, a rare tree of O-ahu, is considered an oddity, since it is the only species in Araliaceae whose flowers have a completely superior ovary. The genus Tetraplasandra has long been known as a close relative of the obsolete genera Gastonia, Reynoldsia, and Munroidendron. This was confirmed by a pollen study in 1971. In 2010, Arthrophyllum, Cuphocarpus, Gastonia, Reynoldsia, Munroidendron, and Tetraplasandra were all sunk into Polyscias, raising the number of species in that genus from about 100 to 159. Four Hawaiian names are applied to groups of Tetraplasandra species. T. hawaiensis is known as -ohe. T. kavaiensis and T. gymnocarpa are called -ohe-ohe. T. waimeae is called -ohe kiko-ola. T. oahuensis and T. lydgatei are called -ohe mauka. The related name, -ohe makai, is applied to Polyscias sandwicensis, formerly known as Reynoldsia sandwicensis. These names closely correspond to clades currently recognized within Tetraplasandra.