Araucarias

Araucarias
	Branches of the Chilean araucaria ( Araucaria araucana )
Systematics
Department :	Vascular plants (tracheophyta)
Subdivision :	Seed plants (Spermatophytina)
Class :	Coniferopsida
Order :	Conifers (Coniferales)
Family :	Araucarias (Araucariaceae)
Genre :	Araucarias
Scientific name
	Araucaria
	Yuss.
Sections
	Araucaria; Bunya; Intermedia; Eutacta;

The araucarias ( Araucaria ) are a genus of plants in the family of the araucarias (Araucariaceae), which belongs to the conifers (Coniferales). It has a strongly disjoint area in the southern hemisphere.

description

Illustration of the Brazilian Araucaria ( Araucaria angustifolia ), cones and branches

Ripe cones and seeds of Araucaria bidwillii

Vegetative characteristics

The Araucaria species are evergreen trees . The species with the tallest specimens from the genus Araucaria is Araucaria hunsteinii at 89 meters . The oldest specimen from the genus is said to be a 1000-year-old Araucaria araucana . Seedlings have two to four cotyledons ( cotyledons ).

On the plagiotropic (plagiotropic: direction of growth determined by geotropism , which does not have the orientation of the stem axis ) aligned branches the coarse leaves are arranged in a spiral. The leaves on young trees are needle-shaped and spiral. In adult trees, the leaves are usually arranged in a scale and spiral or in two layers that overlap. The leaves last for many years. A vegetative propagation of the Araucaria species is not possible because they no longer sprout from cut shoots. As a result, cuttings cannot be propagated from their main roots by the cuttings.

Generative characteristics

Araucaria species are separate sexes, mostly dioecious ( dioecious ) or, less often, monoecious ( monoecious ). Male cones are terminally formed on the branches, individually or in several groups. The numerous stamens are arranged in a spiral. Female cones are almost spherical. The thin cone scales often have a pointed end. The cones become heavy and contain a lot of milky liquid. The cones need two to three years from pollination to maturity. The seeds and scales have grown together. The seeds are winged and in some species are edible.

Cross section through a 210 million year old fossilized cone of Araucaria spec. from Patagonia (Argentina)

Branches with female cones of the Chilean araucaria ( Araucaria araucana )

Brazilian araucaria ( Araucaria angustifolia ) in Petropolis near Rio de Janeiro

Norfolk fir ( Araucaria heterophylla ) as a park tree

Habit of Araucaria humboldtensis

Systematics and distribution

The genus Araucaria was established in 1789 by Antoine Laurent de Jussieu in Genera Plantarum , p. 413. The genus name Araucaria refers to the province of Arauco in southern Chile. Type species is Araucaria imbricata Pav. Nom. illegal. a name that was invalidly published in 1797; therefore one uses the valid new combination Araucaria araucana (Molina) K. Koch des Basionym Pinus araucana Molina .

The genus Araucaria has a strongly disjoint area in the southern hemisphere. There are species in South America , namely in Chile , Argentina and southern Brazil (see also Floresta ombrófila mista ); other species are common in New Caledonia , Norfolk Island , Australia, and New Guinea . This ancient taxon used to have a wider distribution. The recent area is a relic area ; it corresponds to the great continent Gondwana . 14 of the 20 Araucaria species are endemic to New Caledonia; the New Caledonian species are more closely related to each other than any other species.

The genus Araucaria ( Araucaria ) is divided into four sections and contains around 20 species since 2017:

Section Araucaria (Syn .: Sekt. Colymbea (Salisb.) Endl. ): It contains only two species:
- Brazilian araucaria ( Araucaria angustifolia (Bertol.) Kuntze ): It thrives at altitudes of 500 to 1800, sometimes up to 2300 meters in the South American countries Brazil , Argentina and Paraguay .
- Chilean araucaria ( Araucaria araucana (Molina) K. Koch , Syn .: Pinus araucana Molina, Araucaria imbricata Pav. , Araucaria balansae Brong. & Griseb. , Araucaria chilensis (Lam.) Mirb. , Araucaria dombeyi A.Rich. ): You thrives in the Andes at altitudes of 950 to 1050 meters in southern to central Chile and southwestern Argentina.
Section Bunya M.Wilde & AJEames : It contains only one species:
- Queensland Araucaria ( Araucaria bidwillii Hook. ): Several locations of this endemic in Queensland, Australia are known.
Intermedia section : It contains only one type:
- Araucaria hunsteinii K.Schum. (Syn .: Araucaria klinkii Lauterb. , Araucaria schumanniana Warblers. , Araucaria Hunsteinii var. Klinkii (Lauterb) Silba. ): This endemic thrives in altitudes from 600 to 2000 meters only in Bulolo Valley in northeastern New Guinea .
Section Eutacta Endl. : It contains about 15 species:
- Araucaria bernieri J.Buchholz : This endemic thrives at altitudes from 0 to 700 meters in New Caledonia .
- Araucaria biramulata J. Buchholz : This endemic thrives at altitudes of 300 to 1050 meters in New Caledonia.
- Araucaria columnaris (G. Forst.) Hook. : This endemic thrives in the lowlands of New Caledonia. It is used as an ornamental plant in tropical parks because of its particularly beautiful growth.
- New Guinea Araucaria ( Araucaria cunninghamii Aiton ex D.Don ): Some authors differentiate between two varieties:
  - Araucaria cunninghamii Aiton ex D.Don var. Cunninghamii : It thrives in Australia in the tropical coastal and subtropical rainforests at altitudes of 0 to 1000 meters from northern Queensland to Coffs Harbor in New South Wales .
  - Araucaria cunninghamii var. Papuana (Lauterb.) Silba : This endemic thrives at altitudes of 610 to 2400 meters only in the Arfak Mountains in western New Guinea .
- Araucaria goroensis R.R. Mill & Ruhsam : It was first described in 2017 and only occurs in southeastern New Caledonia. So far it has mostly beenconfusedwith Araucaria muelleri . Their occurrence is threatened.
- Common fir ( Araucaria heterophylla (Salisb.) Franco ), also called Norfolk fir. It is available as a houseplant for cool rooms; it is native to the Norfolk Island in the lowlands.
- Araucaria humboldtensis J.Buchholz : This endemic thrives on acidic soils at altitudes of 750 to 1500 meters only on Mt. Humboldt, Mt. Mou and Mt. des Sources in New Caledonia.
- Araucaria laubenfelsii Corbasson : This endemic thrives at altitudes of 400 to 1400 meters only on Mt. Mou, Mt. des Sources, Mt. Dzumac and Mt. Dou in New Caledonia.
- Araucaria luxurians (Brongn. & Gris) de Laub. : This endemic thrives along the coast at altitudes of 200 to 1400 meters in New Caledonia.
- Araucaria montana Brongn. & Gris : This endemic thrives at altitudes of 200 to 1400 meters in the northern part of New Caledonia.
- Araucaria muelleri (Carrière) Brongn. & Gris : This endemic thrives on some mountains at altitudes of 150 to 1400 meters in southeastern New Caledonia.
- Araucaria nemorosa de foliage. : This endemic thrives in the coastal forest at altitudes of up to 100 meters in New Caledonia.
- Araucaria rulei F. Muell. : This rare endemic thrives at altitudes of 150 to 1150 meters in central and southern New Caledonia.
- Araucaria schmidii de foliage. : This endemic only thrives on Mt. Panie at altitudes of 1500 to 1630 meters in New Caledonia.
- Araucaria scopulorum de foliage. : This endemic thrives on the northeast coast up to altitudes of no more than 300 meters in New Caledonia.
- Araucaria subulata Vieill. : This endemic thrives in several locations at altitudes of 320 to 1900 meters in New Caledonia.