ARAUCARIALES, a greater group of coniferous trees, once of cosmopolitan distribu tion, but now restricted to two genera, Arau caria and Dammara, both of the southern hemisphere. The name is derived from Arau cania or Arauco, the district of southern Chile where the superb form Araucaria imbricata of the Nahuel Bute mountains and upper Biobio valley was early observed (1786). The seeds of large size formed an important food of the indigenous Araucanian Indians.
Araucaria imbricata, the Chile pine, Pehuen or monkey puzzle° is the hardiest forest maker of its order. The Andine forest oc cupies the higher volcanic ridges and crests along both flanks from lat. 37° 30' to 40° S. with a width of little more than 100 kilometres, between the altitudes of 600 and 2,000 metres. On the Chilean side there is a heavy snowfall., According to altitude, and to exposure which is• greater in the Argentine extension, the trees vary much in size; but they may grow straight as a granite column to an extreme height of 45 metres and diameter of two or more metres. Both stem and branches of the young trees are closely beset by the imbricating spirals of broadly spinose leaves, as persistent as those of cycads. The stem tends to retain a nearly constant diameter throughout its length as the irregular whorls of lesser lateral branches are constantly shed and overgrown. Only a thick set crown finally surmounts the heavy col umnar trunk. After excision of the leaves the outer bark slowly divides into irregularly poly gonal deeply-pitted plates. The appearance of the trees is singular, that of the pure stand forests remarkable. Like most other members of the Araucariales these trees are character istically dicecious. The staminate cones are larger than in any of the Coniferales, having the size seen in some of the cycads. They are oval, 10 or more centimetres long, by 5 centi metres thick, and borne terminally in groups of four or five in the lateral branches. Ovulate cones are terminal on the lateral branches and may reach a length of 16 centimetres with a diameter of 20. There is a more gradual tran
sition from foliage to fertile leaves than in any other existing gymnosperm. The mega sporophyll bears a single large dicotyledonous seed four or more centimetres long. The wood is rather hard, smooth and durable; but the forests, owing to their isolated position, retain nearly their primaeval facies. In Chile lofty hardwood forests with a dense undergrowth of bamboo give way to the Araucarias. These then extend to the tree line as a more and more open forest. As seen about Llaima and other volcanoes of the Biobio, the sharp transition to grassy slopes, often ending in more or less permanent snow fields, produces a rarely pic turesque effect. Rather the purest stands occur on the Argentine side of the Andes in the lake region between lat. and S. Lago Alumine and other lakes where the trees are abundant have their North American counterparts in the Cascade Mountains south of the heavier coniferous forests and next the dry interior Washington basin. Lake Chelan is one of these physiographic equivalents with like climate and soil. Trees a half metre in diameter with an age of possibly 100 years prove the successful introduction into Cali fornia.
Araucaria brasiliana, the Brazil pine, a closely related more sub-tropical species, is a culminant forest constituent of the uplands of southern Brazil, mainly between 25° and 30°. Especially in the state of Santa Catarina, to the south of the Iguassu River, this tree dominates a remarkable stratified columnar facies. There the open forest is about equally made up of tree ferns three to five metres in height, slender-stemmed palms 10 metres high and the over-topping pines 20 to 30 metres in height. Some outliers of this imposing forest occur further north in the state of Minas Geraes. At Cobijan in the mountains of south eastern Bolivia (lat. 21° S.) there is also a small area of A. brasiliana or a closely related form (A. saviand).