Melicope


Melicope is a genus of about 230 species of shrubs and trees in the family Rutaceae, occurring from the Hawaiian Islands across the Pacific Ocean to tropical Asia, Australia and New Zealand. Plants in the genus Melicope have simple or trifoliate leaves arranged in opposite pairs, flowers arranged in panicles, with four sepals, four petals and four or eight stamens and fruit composed of up to four follicles.

Description

Plants in the genus Melicope have simple or trifoliate leaves arranged in opposite pairs, or sometimes whorled. The flowers are arranged in panicles and are bisexual or sometimes with functionally male- or female-only flowers. The flowers have four sepals, four petals and four or eight stamens. There are four, sometimes five, carpels fused at the base with fused styles, the stigma similar to the tip of the style. The fruit is composed of up to four follicles fused at the base, each with one or two seeds.

Taxonomy

The genus Melicope was first formally described in 1775 by Johann Reinhold Forster and his son Georg Forster in their book Characteres Generum Plantarum and the first species they described was Melicope ternata.
The generic name Melicope is derived from Greek words μελι, meaning "honey," and κοπη, meaning "a division," referring to the glands at the base of the ovary. The Takhtajan system places the genus in the subfamily Rutoideae, tribe Zanthoxyleae.
Evidence from 2009 indicates that the related genus Platydesma of four species is nested within the genus Melicope and is sister to all Hawaiian Melicope species. And while Melicope species are dioecious, the flowers of Platydesma are hermaphroditic, suggesting a rare evolutionary reversion away from dioecy in Platydesma. Molecular phylogenetic analyses also suggest that the genera Comptonella, Dutaillyea, Picrella, and possibly Dutailliopsis, all from New Caledonia, are also nested in Melicope.
The temperate Asian genus Tetradium is closely related to Melicope and is sometimes merged into it.

Ecology

Melicopes are foodplants for various animals, mainly invertebrates. Caterpillars of the Ulysses butterfly are fond of M. elleryana. Caterpillars of Thyrocopa moths have been found on M. clusiifolia. The larvae of some belid weevils from the genus Proterhinus also feed on Melicope although they prefer unhealthy, dying or dead specimens. The plants of some species may not be safe for humans. The nectar of wharangi is known to yield toxic honey that may kill whoever eats it.

Conservation

Several of the Hawaiian species are listed as "endangered" by the Government of the United States of America, due to habitat loss and competition from invasive non-native plants. A few species are already extinct.

Species list

The following is a list of species accepted by the Plants of the World Online as at July 2020: