Melicope is a genus of about 240 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.[2][3][4]
The generic name Melicope is derived from
Greek words μελι (meli), meaning "honey," and κοπη (kope), meaning "a division," referring to the glands at the base of the ovary.[6] The 2009
Takhtajan system placed the genus in the
subfamilyRutoideae,
tribeZanthoxyleae.[7] A 2021 subfamily classification of the Rutaceae, based both on a new and previous
molecular phylogenetic studies, places Melicope (with an expanded
circumscription) in the subfamily
Zanthoxyloideae, stating that the evidence does not yet support classification to tribal level.[8]
Evidence from 2007 onwards showed that with its traditional circumscription, Melicope was not monophyletic. The previously separated genus Platydesma of four species is nested within the genus Melicope and is sister to all Hawaiian Melicope species. And while Melicope species are usually
dioecious (individual plants only bear either male or female flowers), the flowers of the former Platydesma are
hermaphroditic, suggesting a rare evolutionary reversion away from dioecy in Platydesma.[9] Molecular phylogenetic analyses also suggest that the genera Comptonella, Dutaillyea, Picrella, and possibly Dutailliopsis, all from
New Caledonia, might also be nested in Melicope,[10] although they are accepted in the 2021 classification, as is the temperate Asian genus Tetradium,[8] which has sometimes been merged into Melicope (possibly including the tropical Euodia).[11][9]
Ecology
Melicopes are foodplants for various animals, mainly
invertebrates. Caterpillars of the
Ulysses butterfly (Papilio ulysses) 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 (M. ternata) is known to yield
toxic honey that may kill whoever eats it.[12]
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.
^Hartley, Thomas G.; Wilson, Annette J.G. (ed.) (2013).
Flora of Australia (Volume 26). Canberra: Australian Biological Resources Study. p. 95. Retrieved 24 July 2020. {{
cite book}}: |first2= has generic name (
help)
^Hartley, Thomas Gordon (February 2001). "On the Taxonomy and Biogeography of Euodia and Melicope (Rutaceae)". Allertonia. 8 (1): 66.
JSTOR23189298.
^Richards, P.G.
"Genus Melicope". Royal Botanic Garden Sydney. Retrieved 24 July 2020.
^"Melicope". Australian Plant Census. Retrieved 24 July 2020.
^
abAppelhans, Marc S.; Bayly, Michael J.; Heslewood, Margaret M.; Groppo, Milton; Verboom, G. Anthony; Forster, Paul I.; Kallunki, Jacquelyn A. & Duretto, Marco F. (2021), "A new subfamily classification of the Citrus family (Rutaceae) based on six nuclear and plastid markers", Taxon, 70 (5): 1035–1061,
doi:10.1002/tax.12543,
hdl:11343/288824
^
abHarbaugh, D.T.; Wagner, W.L.; Allan, G.J.; Zimmer, E.A. (2009). "The Hawaiian Archipeligo is a stepping stone for dispersal in the Pacific: an example from the plant genus Melicope (Rutaceae)". Journal of Biogeography. 36 (2): 230–241.
doi:
10.1111/j.1365-2699.2008.02008.x.
S2CID56279216.
^Appelhans MS, Wen J, Wagner WL (2014). "A molecular phylogeny of Acronychia, Euodia, Melicope and relatives (Rutaceae) reveals polyphyletic genera and key innovations for species richness". Mol. Phylogenet. Evol. 79: 54–68.
doi:
10.1016/j.ympev.2014.06.014.
PMID24971739.