Amyema

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Amyema

Description

Aerial stem-parasitic shrubs, with or without epicortical runners bearing secondary haustoria. Leaves opposite or verticillate, sometimes displaced and appearing alternate; venation pinnate or curvinerved. Inflorescencess usually axillary, sometimes borne on internodes and/or epicortical runners, basically a pedunculate umbel of dichasia (triads or tetrads), but variously reduced in some species, to a head or simple umbel or solitary flower; rays of the umbel 1-50; bract usually single under each flower, simple or rarely lobed or with a dorsal protuberance. Fruit ellipsoid to ovoid or obovoid.

Distribution

Asia-Tropical:, New Guinea present; Philippines (Philippines present) from the Southeast Asian mainland to Australia and islands of the southwestern Pacific as far as Samoa: present
Genus of 91 species distributed from the Southeast Asian mainland to Australia and islands of the southwestern Pacific as far as Samoa. In Malesia 59 species mostly in the east and south, with centres of diversity in the Philippines and New Guinea.

Ecology

Some species are aggressive, often occurring on cultivated trees. Host specificity varies between species, some having broad host ranges and others having a single preferred host genus or species. Most species of humid forests have low host specificity, occurring on a wide range of dicotyledonous hosts. This is the case even in mangrove communities, where the Amyema species usually occur on several host genera. In seasonal open forests and woodlands the Amyema species may be more closely adapted to parasitize the dominant tree species. In Australia many species show close visual resemblance to common hosts, and mimicry has been suggested.

Taxonomy

For a conspectus of the entire genus, and discussion of species circumscription, relationships and differences, see .