Araucariaceae

See Pinidae for an introduction to these groups

The araucariaceae (scientific name Araucariaceae) are a family of conifers of the Order Araucariales, comprising 3 genera. They are highly resinous, long-lived trees, usually very symmetrical and conical. The cones are solitary, more or less erect, and heavy, the ovuliferous scales each with an ovule, large seeds. The family is practically restricted to the Southern Hemisphere.

Description

Theoretical Introduction in Descriptive Terminology of Plants

Long-lived trees, up to 65 m tall and 6 m in diameter at the base, highly resinous, usually very symmetrical and conical in growth form. Simple leaves, entire, varied in shape (such as awls, scales, linear, oblong or elliptical), sometimes in the same individual, persistent, with a pointed tip in some Araucaria species, spirally arranged or opposite. Dioecious or monoecious. Strobili microsporangiate cylindrical, with numerous microsporophylls arranged in a spiral, each with 4-20 microsporangia, pollen without "sacca", exine dimpled. Solitary cones, more or less erect, heavy, maturing in 2-3 years and finally disintegrating on the tree, ovuliferous scales each with 1 ovule, numerous, spirally arranged, flattened, linear to peltate, the bract more or less long than scale and fused to it, seeds large, with or without marginal wings. Cotyledons 2, sometimes highly divided and resembling 4.

Ecology

Araucariaceae is mostly restricted to the Southern Hemisphere, from Southeast Asia to Australia, New Zealand, and southern South America.

Members of this family usually grow in tropical and subtropical rainforests as well as more temperate areas.

The family is most diverse in New Caledonia, where there are 5 Agathis species and 13 Araucaria species endemic. Species from this area of each genus form a monophyletic group according to rbcL analyses. The small amount of genetic diversification of species within each genus suggests relatively recent radiation in the unusual (ultramafic) soil of New Caledonia.

In some species of Araucaria , the leaves that end in sharp points, the ability to regenerate branches, and the protection of the growth tip by the surrounding branches suggest an adaptation against herbivores that are now extinct.

One of the largest and longest-lived trees in this family is Agathis australis, commonly called Kauri. One particular individual in northern New Zealand was 51.5m tall and 13.8m in circumference and about 2000 years old in early 2001. The Maori name for this individual is Tane Mahuta, which translates to &# 34;god of the forest".

Phylogeny

Theoretical Introduction in Philogenia

The 28S rRNA sequences strongly suggest a sibling relationship between Podocarpaceae and Araucariaceae, sharing the following synapomorphies: one ovule per ovuliferous scale, the ovuliferous scale closely associated with the seed, and possibly the bract fused to the scale.

Agathis and Araucaria differ strongly from one another in their foliar and reproductive structures. The leaves of Agathis are opposite and broad, while those of Araucaria are spirally arranged and linear to broad. Agathis is monoecious with ovules free from the cone scale and has winged seeds. Araucaria is dioecious, with ovules fused to the cone scale and usually has wingless seeds. The DNA sequences of rbcL also support a monophyly of the two genera. The rbcL data are also in agreement with the division of the genus into 4 sections based on non-molecular characters such as number of cotyledons, position of microsporangiate cones, and cellular characters of the leaf epidermis.

Wollemia nobilis was found in 1994 in Wollemi National Park in Sydney, Australia, by "National Park and Wildlife Service" david noble. Known to science before 1994 only as a fossil extending back to 150 million years, it is one of the rarest trees in the world, with only about 43 adults in two populations about 1.5 km apart.. The trees, some of which are between 500 and 1,000 years old, have unusual bark, described as 'bubbly chocolate'.

Taxonomy

Theoretical Introduction in Taxonomy

3 genera, 32 species. The most represented genera are Araucaria (18 species) and Agathis (13 species).

The classification, according to Christenhusz et al. 2011, which also provides a linear sequence of gymnosperms through genus:

• Family 8. Araucariaceae Henkel & W.Hochst., Syn. Nadelhölz.: xvii, 1 (1865), Nom. cons. Type: Araucaria Juss. Synonyms: Dammaraceae Link, Abh. Konigl. Akad. Wiss. Berlin 1827: 157 (1830), nom. illeg. Type: Dammara Link. Agathidaceae (Vierh.) Baum.-Bodenh. ex A.V.Bobrov & Melikian, Komarovia 4: 61 (2006). Type: Agathis Salisb.

3 genera, 41 species, Southeast Asia and the Philippines to Australasia, Pacific, South America.

• • 8.1. Araucaria Juss., Gen. 413 (1789). Type: A. imbricata Pav., nom. illeg. (≡ Pinus araucana Molina) Dombeya Lam., Encycl. Meth., Bot. 2: 301 (1786), nom. illeg., non L’Hér. (1785), No. Type: D. chilensis Lam. nom. illeg. (≡ Pinus araucana Molina) Synonyms: Columbea Salisb, Trans. Linn. Soc. London 8: 317 (1807), nom. illeg. Type: C. quadrifaria Salisb, nom. illeg. (≡ Pinus araucana Molina) Eutassa Salisb, Trans. Linn. Soc. London 8: 316 (1807). Type: E. heterophylla Salisb. (≡ Araucaria heterophylla). Eutacta Link, Linnaea 15: 543 (1842). Type: E. cunninghamii (Aiton ex A. Cunn.) Link (type designated here by Mill & Farjon) (≡ Araucaria cunninghamii Aiton ex A.Cunn.). Quadrifaria Manetti ex Gordon, Pinet. Suppl. 14 (1862). Type: Q. imbricata (Pav.) Manetti ex Gordon (≡) Araucaria araucana). Marywildea A.V.Bobrov & Melikian, Komarovia 4: 57 (2006). Type: M. bidwillii (Hook.) A.V.Bobrov & Melikian (≡) Araucaria bidwillii Hook.). Titanodendron A.V.Bobrov & Melikian, Komarovia 4: 60 (2006). Type: T. hunsteinii (K.Schum.) Araucaria hunsteinii K.Schum.).

• • 8.2. Wollemia W.G.Jones, K.D.Hill & J.M.Allen, Telopea 6: 173 (1995). Type: W. nobilis W.G.Jones, K.D.Hill & J.M.Allen

• • 8.3. Agathis Salisb, Trans. Linn. Soc. London 8: 311 (1807), Nom. cons. Type: A. loranthifolia Salisb, nom. illeg. (≡ Pinus dammara (Lamb.) L.C.Rich.) Synonyms: Dammara Link, Enum. Pl. Horti Berol. 2: 411 (1822), nom. illeg., non Gaertner (1790). Salisburyodendron A.V.Bobrov & Melikian, Komarovia 4: 62 (2006). Type: S. australis (Lamb.) Agathis australis Salisb.).

Evolution

Araucariaceae, like Podocarpaceae, is a distinctive family almost exclusive to the Southern Hemisphere. Its fossil record, particularly that of Araucaria, extends to the Jurassic.

Economic importance

The two most represented genera produce wood. Larger individuals, such as Agathis australis from New Zealand, which can reach 65 m in height and 6 m in diameter, contain large amounts of high-quality wood.

Araucaria heterophylla and Araucaria araucana from Chile are highly prized ornamentals, both as meadow plants and houseplants.