Dombeya  

Dombeya wallichii is a flowering shrub of the family Malvaceae known by the common names pinkball, pink ball tree, and tropical hydrangea. Its native range includes India, East Africa, and Madagascar.^[1]

The plant can grow 20^[2] to 30^[1] feet tall and has a spread of up to 25 feet. The alternately arranged leaves are heart-shaped with serrated edges. The hanging flower clusters are pink, showy,^[2] and fragrant.^[1]

This species can be crossed with Dombeya burgessiae to produce the hybrid Dombeya × cayeuxii.^[1]

References[edit]

Araucaria (pronunciation: /ærɔːˈkɛəriə/)^[4] is a genus of evergreen coniferous trees in the family Araucariaceae. There are 19 extant species in the genus, with a Gondwanan natural distribution in New Caledonia (where 13 species are endemic), Norfolk Island, eastern Australia, New Guinea, Argentina, Chile, and southern Brazil.

Description[edit]

Araucaria araucana with seed cones

Araucaria are mainly large trees with a massive erect stem, reaching a height of 30–80 metres (98–262 ft). The horizontal, spreading branches grow in whorls and are covered with leathery or needle-like leaves. In some species, the leaves are narrow awl-shaped and lanceolate, barely overlapping each other, in others they are broad and flat, and overlap broadly.^[5]

Snow on Araucaria heterophylla

The trees are mostly dioecious, with male and female cones found on separate trees,^[6] though occasional individuals are monoecious or change sex with time.^[7] The female cones, usually high on the top of the tree, are globose, and vary in size between species from 7 to 25 centimetres (2.8 to 9.8 in) diameter. They contain 80–200 large, edible seeds, similar to pine nuts though larger. The male cones are smaller, 4–10 cm (1.6–3.9 in) long, and narrow to broad cylindrical, 1.5–5.0 cm (0.6–2.0 in) broad.

The genus is familiar to many people as the genus of the distinctive Chilean pine or monkey-puzzle tree (Araucaria araucana). The genus is named after the Spanish exonym Araucano ("from Arauco") applied to the Mapuches of central Chile and south-west Argentina whose territory incorporates natural stands of this genus. The Mapuche people call it pehuén, and consider it sacred.^[5] Some Mapuches living in the Andes name themselves Pehuenches ("people of the pehuén") as they traditionally harvested the seeds extensively for food.^[8][9]

No distinct vernacular name exists for the genus. Many are called "pine", although they are only distantly related to true pines, in the genus Pinus.

Distribution and paleoecology[edit]

Three members of the genus growing together – left to right, Araucaria columnaris, Araucaria cunninghamii and Araucaria bidwillii

Members of Araucaria are found in Chile, Argentina, southern Brazil, New Caledonia, Norfolk Island, Australia, and New Guinea. There is also a significant, naturalized population of Araucaria columnaris – "Cook's pine", on the island of Lanai, in Hawaii, USA.^[10] Many if not all current populations are relicts, and of restricted distribution. They are found in forest and maquis shrubland, with an affinity for exposed sites. These columnar trees are living fossils, dating back to early in the Mesozoic age. Fossil records show that the genus also formerly occurred in the northern hemisphere until the end of the Cretaceous period. By far the greatest diversity exists in New Caledonia, due to the island's long isolation and stability.^[5]

It is believed that the long necks of sauropod dinosaurs may have evolved specifically to browse the foliage of the typically very tall Araucaria trees. The global distribution of vast forests of Araucaria during the Jurassic makes it likely that they were the major high energy food source for adult sauropods.^[11]

Classification and species list[edit]

Araucaria columnaris sapling with distinctive axial bud.

The leaves of Araucaria heterophylla

Petrified cone of Araucaria mirabilis from Patagonia, Argentina dating from the Jurassic Period (approx. 157 mya)

Araucaria sp., either A. angustifolia or hybrid A. angustifolia × A. araucana; cultivated, Santa Rosa, Argentina.

There are four extant sections and two extinct sections in the genus, sometimes treated as separate genera.^[5][12][13] Genetic studies indicate that the extant members of the genus can be subdivided into two large clades – the first consisting of the section Araucaria, Bunya, and Intermedia; and the second of the strongly monophyletic section Eutacta. Sections Eutacta and Bunya are both the oldest taxa of the genus, with Eutacta possibly older.^[14]

Taxa marked with † are extinct.

• Section Araucaria. Leaves broad; cones more than 12 cm (4.7 in) diameter; seed germination hypogeal. Syn. sect. Columbea; sometimes includes Intermedia and Bunya
  • Araucaria angustifolia – "Paraná pine" (obsolete: "Brazilian pine", "candelabra tree"; southern Brazil, northeastern Argentina
  • Araucaria araucana – "monkey-puzzle" or "pehuén" (obsolete: "Chile pine"); central Chile & western Argentina
  • †Araucaria nipponensis – Japan^[15]
• Section Bunya. Contains only one living species. Produces recalcitrant seeds with hypogeal (cryptocotylar) germination,^[16] though extinct species may have exhibited epigeal germination.^[14]
  • Araucaria bidwillii – "bunya-bunya"; Eastern Australia
  • †Araucaria brownii
  • †Araucaria mirabilis – Patagonia
  • †Araucaria sphaerocarpa
• Section Intermedia. Contains only one living species. Produces recalcitrant seeds
  • Araucaria hunsteinii – "klinki"; New Guinea
  • †Araucaria haastii
• Section Eutacta. Leaves narrow, awl-like; cones less than 12 cm (4.7 in) diameter; seed germination epigeal
  • Araucaria bernieri – New Caledonia
  • Araucaria biramulata – New Caledonia
  • Araucaria columnaris – "Cook pine"; New Caledonia
  • Araucaria cunninghamii – "Moreton Bay pine", "hoop pine"; Eastern Australia, New Guinea
  • Araucaria heterophylla – "Norfolk Island pine"; Norfolk Island
  • Araucaria humboldtensis – New Caledonia
  • Araucaria laubenfelsii – New Caledonia
  • Araucaria luxurians – New Caledonia
  • Araucaria montana – New Caledonia
  • Araucaria muelleri – New Caledonia
  • Araucaria nemorosa – New Caledonia
  • Araucaria rulei – New Caledonia
  • Araucaria schmidii – New Caledonia
  • Araucaria scopulorum – New Caledonia
  • Araucaria subulata – New Caledonia
• †Section Yezonia. Extinct. Contains only one species
  • †Araucaria vulgaris – Japan
• †Section Perpendicula. Extinct. Contains only one species
  • †Araucaria desmondii
• incertae sedis
  • †Araucaria fibrosa
  • †Araucaria beipiaoensis
  • †Araucaria nihongii – Japan
  • †Araucaria taieriensis

Araucaria bindrabunensis (previously classified under section Bunya) has been transferred to the genus Araucarites.

Uses[edit]

Some of the species are relatively common in cultivation because of their distinctive, formal symmetrical growth habit. Several species are economically important for timber production. The edible large seeds of A. araucana, A. angustifolia and A. bidwillii are also eaten as food (particularly among the Mapuche people and Native Australians).^[5]

Pharmacological activity[edit]

Pharmacological reports on genus Araucaria are anti- ulcer, antiviral, neuro-protective, anti-depressant and anti-coagulant.^[17]

In popular culture[edit]

• An Araucaria is featured prominently in Herman Hesse's novel Steppenwolf.
• The Araucaria forests of New Caledonia and Chile are used as Triassic forested plains of Arizona and New Mexico, Jurassic open woodlands of Colorado and forested islands of Oxfordshire, and especially Cretaceous forests, and open plains of Montana in Walking with Dinosaurs and the same environments are used again in the first episode of Prehistoric Park.
• An Araucaria forest of Patagonia is also used as "prehistoric background" in Discovery Channel's When Dinosaurs Roamed America, National Geographic's Dino Death Trap, and especially the 2007 film Dinosaurs: Giants of Patagonia.
• Araucaria was the pseudonym of the crossword compiler John Galbraith Graham (1921–2013).

See also[edit]

• Agathis (Kauri)
• Wollemia

References[edit]