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The Araucariaceae, commonly referred to as araucarians, are a very ancient family of coniferous trees. The group achieved its maximum diversity in the Jurassic and Cretaceous periods, when it was distributed almost worldwide. At the end of the Cretaceous, when the non-avian dinosaurs became extinct, so did most of the Araucariaceae in the Northern Hemisphere. At least one genus, possibly ''Agathis'', survived into the Eocene. ==Description== Members of Araucariaceae are typically very tall evergreen trees,〔(【引用サイトリンク】title=Araucariaceae )〕 reaching heights of or more.〔(【引用サイトリンク】title=Araucariaceae: life history and ecology )〕 They can also grow very large. A New Zealand kauri tree (''Agathis australis'') named ''Tāne Mahuta'' ("The Lord of the Forest") has been measured at tall with a diameter at breast height of . Its total wood volume is calculated to be ,〔(【引用サイトリンク】title=Agathis australis )〕 making it the third-largest conifer after ''Sequoia'' and ''Sequoiadendron'' (both from the Cupressaceae subfamily Sequoioideae).〔 The trunks are columnar and have relatively large piths with resinous cortices. The branching is usually horizontal and tiered, arising regularly in whorls of three to seven branches or alternating in widely separated pairs. The leaves can be small, needle-like, and curved, or they can be large, broadly ovate, and flattened. They are spirally arranged, persistent, and usually have parallel venation.〔 Like other conifers, they produce cones. Each tree can have both male and female cones (monoecious) or they can have only male or female cones (dioecious). Male cones are among the largest among all conifer cones, on average. They are cylindrical and drooping, somewhat (resembling catkins). They are borne singly on the tips of branches or the axils of leaves. They contain numerous sporophylls arranged in whorls or spirals. Each has four to 20 elongated pollen sacs attached to the lower surface at one end. The pollen grains are round and do not possess wings or air sacs.〔〔〔 Female cones are also very large. They are spherical to ovoid in shape and borne erect on thick, short shoots at branch tips. The numerous bracts and scales are either fused to each other or separate for half of their lengths.〔〔〔 The scales almost always bear only one seed on its upper surface, in contrast to two in true pines (family Pinaceae). They are very large, among the largest seeds among conifers. They are dispersed by wind, usually using wing-like structures. On maturity, the female cones detach and fall to the ground.〔〔〔 Due to their size, they can cause serious injuries if they hit a person. The cones of the bunya bunya, ''Araucaria bidwillii'', for example, weigh , about the size and weight of a large pineapple. They can drop from heights of .〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Araucariaceae」の詳細全文を読む スポンサード リンク
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