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A rooted phylogenetic tree (see two graphics at top) is a directed tree with a unique node — the root — corresponding to the (usually imputed) most recent common ancestor of all the entities at the leaves of the tree. The root node does not have a parent node, but serves as the parent of all other nodes in the tree.
When a directed rooted tree has an orientation away from the root, it is called an arborescence [3] or out-tree; [11] when it has an orientation towards the root, it is called an anti-arborescence or in-tree. [11] The tree-order is the partial ordering on the vertices of a tree with u < v if and only if the unique path from the root to v passes ...
Edward Hitchcock's fold-out paleontological chart in his 1840 Elementary Geology. Although tree-like diagrams have long been used to organise knowledge, and although branching diagrams known as claves ("keys") were omnipresent in eighteenth-century natural history, it appears that the earliest tree diagram of natural order was the 1801 "Arbre botanique" (Botanical Tree) of the French ...
Boscia albitrunca, commonly known as the shepherd tree or shepherd's tree (Afrikaans: Witgat, Sotho: Mohlôpi, Tswana: Motlôpi, Venda: Muvhombwe, Xhosa: Umgqomogqomo, Zulu: Umvithi), is a protected species of South African tree in the caper family. [1] It is known for having the deepest known root structure of any plant at: -68 metres (223 ft ...
Graphs with multiple nodes designated as roots are also of some interest in combinatorics, in the area of random graphs. [4] These graphs are also called multiply rooted graphs. [5] The terms rooted directed graph or rooted digraph also see variation in definitions. The obvious transplant is to consider a digraph rooted by identifying a ...
A tree structure, tree diagram, or tree model is a way of representing the hierarchical nature of a structure in a graphical form. It is named a "tree structure" because the classic representation resembles a tree, although the chart is generally upside down compared to a biological tree, with the "stem" at the top and the "leaves" at the bottom.
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The tree's stems live no more than 600 years, but its root system's age [75] [76] was established using carbon dating and genetic matching. [77] Elsewhere in the Fulu mountains, 20 spruces have been found older than 8,000 years. [78] Old Rasmus: 9,500: Norway spruce Picea abies: Sonfjället, Härjedalen: Sweden [79] Mongarlowe mallee: 3,000 ...