Olearia albida

Olearia albida, also known by the name tanguru or tree daisy,^[2] is a species of flowering plant in the family Asteraceae. The plant was first described by Joseph Dalton Hooker in 1864, and is endemic to the northern North Island of New Zealand, often found in coastal areas.

Olearia albida
Conservation status
Declining (NZ TCS)[1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Asterales
Family:	Asteraceae
Genus:	Olearia
Species:	O. albida
Binomial name
Olearia albida (Hook.f.) Hook.f.

Taxonomy

The species was formally described by Joseph Dalton Hooker in 1864.^[3] The species epithet albida is based on the Latin word alba, meaning "somewhat white".^[4]

The species' closest relative is Olearia paniculata from which it diverged an estimated 1.8 million years ago. The Olearia genus is thought to have speciated around 3.5 million years ago, and is most closely related to the genus Celmisia (New Zealand daisies).^[5]

Description

Hooker's original type description of the species is as follows:

A small tree, very like O. Forsteri in habit and foliage, but the leaves are not evidently reticulate on either surface, the under surface is rather softer and very white, the panicles larger, more effuse. Heads quite different, pedicelled, 0.2 in (5.1 mm). long, subcylindric; involucral scales imbricate, short, obtuse, pubescent; florets 2 or 3, one often ligulate; pappus white, unequal. Achene pubescent.^[3]

The species has grooved, flaky bark and light green leaves with a white underside, that are typically wavy. The species has white flowers that typically form in clusters.^[4] The species can grow to a height of up to 5 m (16 ft) tall.^[6]

Distribution and habitat

The species is endemic to New Zealand, found on the North Island as far south as northern Taranaki, as well as on offshore islands of the Hauraki Gulf.^[4] Some hotspot locations for the species include Tāpapakanga Regional Park and the northern shores of the Matakana River mouth.^[6]

The species is found in coastal areas, typically headlands and areas with loose soil (such as slip scars).^[4]

Conservation

While the species is widely distributed, many populations are in decline, threatened by invasive weeds, coastal erosion and animal browsing.^[4] While previous considered a non-threatened plant, in 2024 the New Zealand Threat Classification System upgraded its rating of the species from Not Threatened to Declining.^[1]

Gallery

• 
  Specimen from the herbarium of the Auckland War Memorial Museum
• 
  Flowers of Olearia albida
• 
  Leaves of Olearia albida
• 
  A tall Olearia albida growing at the Dunedin Botanic Gardens