Gastonia (plant)

Gastonia Commerson ex Lamarck is a formerly accepted genus of plants in the ivy and ginseng family, Araliaceae.

It had been known as an unnatural group, but was recognized as late as 2010, when its nine species[1] were distributed to four different subgenera of the large genus Polyscias.

The species that constituted Gastonia are mostly island endemics, with Madagascar and New Guinea being the largest land masses on which any of them naturally occur.

It is distinguished from Reynoldsia, Munroidendron, and Tetraplasandra by the radiating style arms that persist on the fruit.

[3] This description was a large and unexpected taxonomic error because Terminalia is in the Myrtalean family Combretaceae.

[10] Quattrocchi states that Gastonia was "named after Gaston d'Orléans, 1608-1660, a patron and promoter of botany and floriculture".

[11] The name was originated by Philibert Commerson,[12][13] but validated later, in 1788, by Jean-Baptiste Lamarck in Encyclopédie Méthodique.

[14] Lamarck gave a detailed description of the species that he named Gastonia cutispongia.

In 1898, Hermann Harms transferred what is now Polyscias sechellarum to Gastonia in a landmark monograph on Araliaceae in Die Natürlichen Pflanzenfamilien.

Since that time, molecular phylogenetic studies, based on DNA sequences, have shown that Gastonia was polyphyletic.

Six genera (Arthrophyllum, Cuphocarpus, Gastonia, Reynoldsia, Munroidendron, and Tetraplasandra) were placed in synonymy under Polyscias.

In accordance with the phylogenetic studies of DNA, Polyscias was divided into 11 subgenera (Polyscias, Grotefendia, Maralia, Arthrophyllum, Cuphocarpus, Tetraplasandra, Eupteron, Sciadopanax, Tieghemopanax, Indokingia, and Palmervandenbroekia) and seven species were left incertae sedis.

Polyscias sechellarum was divided into three varieties in 1987,[19] but some authors have declined to recognize them until further studies can be done on this species.

Eleven species are endemic to Hawaii, and ten others are distributed in a large area that includes Malesia and extends eastward to Tahiti.

[2] Gregory M. Plunkett, Jun Wen, Porter P. Lowry II, Murray J. Henwood, Pedro Fiaschi, and Anthony D. Mitchell.