Melicope oppenheimeri, section Pelea (Rutaceae), a new species from West Maui, Hawaiian Islands: with notes on its ecology, conservation, and phylogenetic placement

Abstract

Melicope oppenheimeri K.R. Wood, Appelhans & W.L. Wagner (section Pelea (A. Gray) Hook. f., Rutaceae), a rare endemic tree from West Maui, Hawaiian Islands, is described and illustrated with notes on its ecology, conservation, and phylogenetic placement. The new species differs from Hawaiian congeners by its carpels basally connate 1/5, narrowed into a strongly reflexed beak 10–15 mm long. It also differs in a combination of leaves with 7–10 pair of secondary veins; cymes to 3 cm long; peduncles 5–6.5 mm long; flowers perfect; capsules 4–9 × 40–52 mm; and a densely appressed short-sericeous ovary. Melicope oppenheimeri is known only from an isolated cliff-base plateau in upper Waihe‘e Valley, West Maui. Its discovery brings the number of recognized Melicope J.R. Forst. & G. Forst. species in the Hawaiian Islands to 49. A table is included indicating the conservation status of Hawaiian Melicope and Platydesma H. Mann., which is nested within Melicope sect. Pelea.Melicope oppenheimeri falls into the IUCN (CR)Critically Endangered Red List category.

Phylogeny of Hawaiian Melicope (Rutaceae): RAD-seq Resolves Species Relationships and Reveals Ancient Introgression

“…Two samples represent the two independent colonization events to the Marquesas Islands (28% of Marquesan species). Taxonomic treatment follows species recognized in Wood et al (2016) plus a recently described species (Wood et al, 2017) and including Platydesma (Appelhans et al, 2017). Additionally, morphologically divergent specimens of Melicope barbigera (KW16722 and KW16718) and Melicope ovata (KW16762, KW17082, and MA663) were included ( Table 1 , asterisk) to elucidate whether these might represent separate taxa.…”

Melicope stonei, section Pelea (Rutaceae), a new species from Kaua‘i, Hawaiian Islands: with notes on its distribution, ecology, conservation status, and phylogenetic placement

“…consists of ca. 235 species of shrubs and trees with a distribution that ranges from the Malagasy and Indo-Himalayan regions in the east to the Hawaiian and Marquesan Islands in the west and from Nepal, southern China, Taiwan and the Japanese Ogasawara Islands in the north to New Zealand and Australia in the south (Hartley 2001, Appelhans et al 2014a, Wood et al 2016a). With the inclusion of Melicope stonei K.R.…”

“…Wood, Appelhans & W.L. Wagner, the total number of recognized Melicope reported for the Hawaiian Islands totals 50 endemic species, making Melicope the most species-rich radiation of woody plants throughout the archipelago (Hillebrand 1888, Hartley and Stone 1989, Wagner et al 1999, Wood et al 2016a). Molecular phylogenetic studies indicate that the Hawaiian species arose from a single introduction, and that the Hawaiian genus Platydesma H. Mann is nested within Melicope section Pelea (A.…”

Reduction of the Hawaiian genus Platydesma into Melicope section Pelea (Rutaceae) and notes on the monophyly of the section

“…Hartley & B.C. Stone, are presumed to be extinct and 11 species are known from 50 or less living individuals in the wild (Wagner et al 1999, Wood 2011, 2014, Wood et al 2016). …”