Lomatia is a genus of 12 species of evergreen flowering plants in the family Proteaceae (order Proteales), traditionally placed alone in the subtribe Lomatiinae. The genus has a distinctive Pacific Rim distribution, with species native to eastern Australia (including Tasmania) and southern South America (Chile, Argentina, and Peru), a pattern shared with other members of the Antarctic flora — a disjunct group of plants that reflects ancient Gondwanan land connections.
Members of the genus range considerably in stature, from prostrate shrubs less than 0.5 m (1.6 ft) tall to small trees reaching up to 12 m (39 ft). All species are evergreen, a characteristic typical of the family Proteaceae. The genus includes both fire-adapted and non-fire-adapted species, with representatives occupying montane shrublands, wet forests, and heath communities across its range.
Phylogenetic analysis using microsatellite markers has revealed that species found in geographic proximity are most closely related to one another. The South American species — Lomatia dentata, L. hirsuta, and L. ferruginea — diverged successively from the lineage that gave rise to the Australian species. Among Australian species, the three Tasmanian taxa form a clade, with L. tasmanica sister to the other two Tasmanian species, and this Tasmanian group in turn sister to the mainland Australian species. On the mainland, the far-northern Queensland species L. fraxinifolia is the outgroup to the five southeastern Australian species.
One of the most remarkable members of the genus is Lomatia tasmanica (King's lomatia), a Tasmanian endemic that is unable to reproduce sexually and persists entirely through vegetative cloning; it is one of the world's most endangered plant species. Other well-known species include L. tinctoria and L. polymorpha, both Tasmanian endemics known colloquially as guitarplant and mountain guitarplant respectively, and L. silaifolia of eastern Australia.
Distribution
Lomatia has a Pacific Rim distribution, with species native to eastern Australia (including Tasmania) and southern South America (Chile, Argentina, and Peru). This disjunct range reflects the genus's membership in the Antarctic flora — a group whose distribution traces ancient Gondwanan land connections. Australian and South American species form distinct genetic clades consistent with their geographic separation.
Taxonomy Notes
Within Proteaceae, Lomatia is placed alone in the subtribe Lomatiinae, as recognised by Johnson & Briggs (1975) and subsequently adopted in the Flora of Australia (1995). Molecular phylogenetic work using microsatellite markers has clarified relationships within the genus, showing that geographic proximity closely predicts phylogenetic relatedness. The genus comprises approximately 12 extant species, with several fossil species known from Eocene and Oligocene–Miocene deposits in Patagonia.
Conservation
Lomatia tasmanica (King's lomatia) is one of the world's most endangered plant species. The species cannot reproduce sexually and persists as a single clonal population in southwestern Tasmania, maintained entirely through vegetative reproduction. All known individuals are genetically identical triploids, making the species highly vulnerable to any disturbance. Its existence over thousands of years is known from fossil evidence, indicating it has persisted clonally for an extraordinary length of time.
