Archirhodomyrtus is a genus of flowering plants in the myrtle family Myrtaceae, order Myrtales. Described as a genus in 1941, it comprises five known species of trees and shrubs. The genus is characterised by oppositely arranged leaves, with flowers borne solitarily, in pairs, or in threes in the leaf axils. Each flower has five sepals, five petals, and numerous stamens. The fruit is a smooth berry containing many seeds.
The Australian species, Archirhodomyrtus beckleri — commonly known as Rose Myrtle — is a shrub or small tree reaching up to 6 metres in height. Its branchlets are red-brown, and its leaves are lanceolate to ovate-elliptic, 3–8.5 cm long, with a glossy upper surface and paler underside, bearing small but numerous oil glands. Flowers are mostly solitary with obovate to elliptic petals 4.5–6 mm long, coloured white or pink, with deep pink stamens 2.5–3.5 mm in length. The ovary is 3-locular. The fruit is a globose to ovoid smooth berry, 5–7 mm in diameter, ripening from yellow to orange. Flowering occurs in spring. The remaining four species — A. baladensis, A. paitensis, A. turbinata, and A. vieillardi — are endemic to New Caledonia.
Distribution
The genus Archirhodomyrtus has five recognised species, four of which are endemic to New Caledonia. The sole Australian species, Archirhodomyrtus beckleri (Rose Myrtle), occurs in eastern Australia — from north of the Williams River in New South Wales northward into Queensland — where it grows in rainforest and on rainforest margins.
Taxonomy
Archirhodomyrtus was described as a distinct genus in 1941 within the family Myrtaceae (order Myrtales). The authorship is attributed to Burret. The Australian species A. beckleri was originally described by Ferdinand von Mueller and later revised by A.J. Scott; it was formerly placed under Rhodomyrtus as Rhodomyrtus beckleri. GBIF records four descendant species under the genus, while Wikipedia and other floras recognise five.
Ecology
The Australian species Archirhodomyrtus beckleri grows in rainforest and on rainforest margins in eastern Australia. The four New Caledonian species are likewise associated with forest habitats on that island.
