''Pachystegia'' is a genus of shrubs in the family Asteraceae, known as

Marlborough Marlborough may refer to: Places United Kingdom * Marlborough, Wiltshire, England ** Marlborough College, public school * Marlborough School, Woodstock in Oxfordshire, England * The Marlborough Science Academy in Hertfordshire, England Austral ...

rock daisies, with distinctive leathery leaves and daisy-like flowers. They are naturally found only in dry areas of the north-eastern

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

of New Zealand.

Taxonomy

''Pachystegia'' was first described by Joseph Hooker in 1855 from specimens collected along the banks of the Waihopai River, Marlborough. Hooker placed it in the tree daisy genus '' Olearia'', naming it ''Olearia insignis''. In 1915

Thomas Cheeseman Thomas Frederick Cheeseman (8 June 184515 October 1923) was a New Zealand botanist. He was also a naturalist who had wide-ranging interests, such that he even described a few species of sea slugs (marine gastropod molluscs). Biography Chees ...

named a smaller variety ''O. insignis'' var. ''minor;'' eventually he decided the species was sufficiently different from tree daisies to warrant its own genus, ''Pachystegia,'' meaning “thickly covered”, referring to the dense hairs on the undersides of its leaves. Later field study and analysis of

flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

s suggested there were at least six taxonomic entities in ''Pachystegia.'' ''P. minor'' was elevated to species status, and ''P. rufa'' named, but several species remain undescribed.

Described species

* ''

Pachystegia insignis ''Pachystegia insignis'' is a species of flowering plants in the family Asteraceae. It is endemic to New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses— ...

'' (Hook.f.) Cheeseman * ''

Pachystegia minor ''Pachystegia'' is a genus of shrubs in the family Asteraceae, known as Marlborough Region, Marlborough rock daisies, with distinctive leathery leaves and daisy-like flowers. They are naturally found only in dry areas of the north-eastern South ...

'' (Cheeseman) Molloy * ''

Pachystegia rufa ''Pachystegia'' is a genus of shrubs in the family Asteraceae, known as Marlborough rock daisies, with distinctive leathery leaves and daisy-like flowers. They are naturally found only in dry areas of the north-eastern South Island of New Zealan ...

'' Molloy

Description

''Pachystegia'' is adapted to drought, and grows on dry inland hills and coastal cliffs – it is often restricted to inaccessible rocky bluffs and cliffs, out of the reach of introduced sheep, goats, and rabbits. It often occurs with the other drought-tolerant shrubs ''

Veronica hulkeana ''Veronica hulkeana'', synonym ''Hebe hulkeana'', the New Zealand lilac, is a species of plant in the Plantaginaceae Plantaginaceae, the plantain family, is a large, diverse family of flowering plants in the order Lamiales that includes comm ...

'' and ''

Brachyglottis monroi ''Brachyglottis monroi'' (Monro's ragwort; syn. ''Senecio monroi'') is a species of plant in the family Asteraceae, formerly classified in the genus ''Senecio''. Native to New Zealand and Tasmania, it is a small, hardy, evergreen shrub growing to ...

''. All species are low spreading shrubs with leaves that are thick and leathery and white-furred below. Their white daisy flowers have distinctive large buds covered with overlapping scales. Hybridisation between described and undescribed species is common; some hybrid cultivars of ''P. insignis'' and ''P. minor'' are popular around the world as garden plants.

Distribution

The entire genus is endemic to Marlborough and North Canterbury in the

of New Zealand. '' Pachystegisa insignis'' is widespread, found from the Wairau River in the north to the

Waiau Uwha River Waiau Uwha River, previously known as the Waiau River, is a river in north Canterbury in the South Island of New Zealand. The Waiau Uwha River rises in the Spenser Mountains and flows eastward to the Pacific Ocean. The Waiau Uwha River has th ...

in Canterbury. ''P. rufa'' and ''P. minor'' have much smaller ranges, and the latter is considered a threatened species. ''Pachystegia'' species are often found on the coast, but they occur as far inland as

Molesworth Station Molesworth Station is a high country cattle station. It is located behind the Inland Kaikoura Mountain range in the South Island's Marlborough District. It is New Zealand's largest farm, at over and supports the country's biggest herd of ...

and the Upper Awatere River valley. The most endangered is the

Ōhau rock daisy ''Pachystegia'' is a genus of shrubs in the family Asteraceae, known as Marlborough rock daisies, with distinctive leathery leaves and daisy-like flowers. They are naturally found only in dry areas of the north-eastern South Island of New Zealan ...

, an undescribed species found only on Ōhau Point north of Kaikōura.

References

External links

* * Ōhau rock daisy discussed on

RNZ Radio New Zealand ( mi, Te Reo Irirangi o Aotearoa), commonly known as Radio NZ or simply RNZ, is a New Zealand public-service radio broadcaster and Crown entity that was established under the Radio New Zealand Act 1995. It operates news and cu ...

''Critter of the Week''
1 December 2017
{{Authority control Astereae Asteraceae genera Endemic flora of New Zealand Plants described in 1925 Taxa named by Thomas Frederic Cheeseman