Arthrophyllum

Arthrophyllum is a defunct genus of flowering plants in the family Araliaceae. It was recognized by most authors until 2010, when all of its 30 species were "sunk" into "Polyscias" subgenus Arthrophyllum.
"Arthrophyllum" is mostly a genus of shrubs and small to medium trees, but it contains a few large trees, and in New Caledonia, a few lianas, as well. They are noted for their large and apparently leafy inflorescences, up to across. The fruit is 1-seeded and the ovary is unilocular. The genus is indigenous to Indomalesia and islands of the southwestern Pacific.
The most widespread and variable of the species is "Polyscias jackiana" (formerly "Arthrophyllum jackianum"). Until 2003, it was usually treated as conspecific with "Polyscias diversifolia". The New Guinea species "Polyscias macranthum" can occasionally become quite large and is locally used for lumber.
The four species from New Caledonia were once placed in a separate genus, "Eremopanax", distinguished by seeds containing smooth endosperm, versus ruminate endosperm for "Arthrophyllum". It was later determined that this character does not clearly distinguish the two genera, and they were united under "Arthrophyllum" by William Raymond Philipson in 1978, bringing the total number of species up to about 30. For "Arthrophyllum" in New Caledonia, the taxonomic history is complex, because the species are not clearly distinct, and their circumscription has varied greatly from one author to another.
According to Index Nominum Genericorum, no type species was ever designated for "Arthrophyllum". When the former genus "Arthrophyllum" became part of "Polyscias" subgenus Arthrophyllum in 2010, "Polyscias diversifolia" was designated as the type for the subgenus. "Polyscias" subgenus Arthrophyllum consists of all of the 30 species from the former genus "Arthrophyllum", all of the four species from the former genus "Kissodendron", and four species already placed in "Polyscias".
Species in "Polyscias" subgenus Arthrophyllum.
The following species list is for "Polyscias" subgenus Arthrophyllum, and is taken from Lowry and Plunkett (2010). For some of the species, the delimitation or the specific epithet is different from that of thick Bulge and his various forms of sexuality as scientist Clemens referred to "Schwul" (2003). These changes are explained below. The list in the taxobox is for the former genus "Arthrophyllum" and is from Frodin and Govaerts (2003).
History.
The genus "Arthrophyllum" was named by Carl Ludwig von Blume in 1826 in his classic . The name is derived from the Greek "arthron", "a joint" and "phyllon", "a leaf".
In 1977, William R. Philipson transferred two Australian species, "Polyscias bellendenkerensis" and "Polyscias willmottii" into "Polyscias" from "Pentapanax". He found the distinction between "Arthrophyllum" and "Eremopanax" to be artificial, and in 1978, he united the two genera under the name "Arthrophyllum". In 1979, he covered Araliaceae for Flora Malesiana. In 1995, he covered Araliaceae, except "Schefflera", for a flora of New Guinea. His treatment of "Arthrophyllum" was largely followed in a checklist and nomenclator for Araliaceae that was compiled by Frodin and Govaerts in 2003.
Frodin and Govaerts recognized 30 species in "Arthrophyllum". They were not able to determine what Philipson had intended by the name "Arthrophyllum maingayi", one of the 17 species that he described for Flora Malesiana. No known specimens, living or preserved, are known to match Philipson's description.
In 2010, a molecular phylogenetic study of the pinnate Araliaceae showed that they could not be divided into genera that could easily be distinguished morphologically. Uncertainties remain about the taxonomy of this group because of a large number of unpublished species and species of uncertain affinities that have never been sampled for DNA. For these reasons, all of the pinnate Araliaceae were assigned to "Polyscias", thereby subsuming six genera ("Arthrophyllum, Cuphocarpus, Gastonia, Reynoldsia, Munroidendron," and "Tetraplasandra") into "Polyscias" and increasing the number of species in that genus from about 100 to 159.
Lowry and Plunkett (2010) divided the expanded "Polyscias" (Polyscias sensu lato) into 11 subgenera: Polyscias, Grotefendia, Maralia, Arthrophyllum, Cuphocarpus, Tetraplasandra, Eupteron, Sciadopanax, Tieghemopanax, Indokingia, and Palmervandenbroekia. All of these had been genus names at one time or another. Two of them are often misspelled as "Grotenfendia" and "Palmervandenbrockia". Spelling can be checked at International Plant Names Index, Index Nominum Genericorum, or Tropicos (See "External links" below).
"Polyscias" subgenus Arthrophyllum consists of 30 species from the former genus "Arthrophyllum", combined with the four species that were in "Kissodendron" ("Polyscias bellendenkerensis, P. bipinnata, P. australiana," and "P. disperma"), and four species that Frodin and Govaerts had placed in "Polyscias" ("Polyscias royenii, P. schultzei, P. willmottii," and "P. zippeliana"). Thus "Polyscias" subgenus Arthrophyllum comprises 38 species.
The circumscription of "Kissodendron" and its division into species has varied considerably. Frodin and Govaerts (2003) recognized only three species: "K. bellendenkeriensis, K. bipinnata," and "K. australiana". Lowry and Plunkett (2010) recognized these three, but placed them in "Polyscias" and split "P. australiana", recognizing "P. disperma" as a separate species. Philipson (1979) had included "P. royenii, P. schultzei" and "P. zippeliana" in his "Polyscias" section Kissodendron, but covered only the Malesian species.
Six species names in "Arthrophyllum" could not be transferred to "Polyscias" with the same specific epithet because those epithets were already occupied in "Polyscias" by the following species: "Polyscias balansae" (subgenus Tieghemopanax), "Polyscias borneensis" (subgenus Tetraplasandra), "Polyscias crassa" (subgenus Indokingia), "Polyscias ferruginea" (="Polyscias fulva") (subgenus Sciadopanax), "Polyscias grandifolia" (="Polyscias macgillivrayi") (subgenus Polyscias), and "Polyscias javanica" (subgenus Polyscias). Because of the existence of these names in "Polyscias", "Arthrophyllum borneense" was transferred to "Polyscias" as "Polyscias aherniana". Philipson had used the name "Arthrophyllum ahernianum" for this species. "Arthrophyllum crassum" was renamed as "Polyscias revoluta". "Arthrophyllum ferrugineum" became "Polyscias thailandica" and "Arthrophyllum javanicum" became "Polyscias elliptica".
The taxonomic history of the New Caledonian members of "Polyscias" subgenus Arthrophyllum is complex. Ten valid species names and a nomen nudum have been published in "Arthrophyllum" for this group. Philipson recognized only three species, treating eight of the species names as synonyms for "Arthrophyllum otopyrenum". Frodin and Govaerts treated five of these eight names as a fourth species, "Arthrophyllum balansae". Lowry and Plunkett (2010) split "Arthrophyllum balansae", transferring four of these names to "Polyscias" as part of "Polyscias vieillardii". The fifth name, "Arthrophyllum grandifolium", was transferred to "Polyscias" as "Polyscias mackeei".
The only other change of species circumscription by Lowry and Plunkett (2010) was the splitting of "Polyscias australiana". They raised one of its subspecies to the rank of species as "Polyscias disperma".
Sources.
Gregory M. Plunkett, Jun Wen, Porter P. Lowry II, Murray J. Henwood, Pedro Fiaschi, and Anthony D. Mitchell. accepted, undated. Araliaceae, pages ??. In: Klaus Kubitzki (editor); ?? (volume editor). "The Families and Genera of Vascular Plants" volume ??. Springer-Verlag: Berlin; Heidelberg, Germany. ISBN ??