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Taxonomy

Pines are gymnosperms. The genus is divided into two subgenera based on the number of fibrovascular bundles in the needle. The subgenera can be distinguished by cone, seed, and leaf characters:

Phylogenetic evidence indicates that both subgenera have a very ancient divergence from one another. Each subgenus is further divided into sections and subsections.

Many of the smaller groups of Pinus are composed of closely related species with recent divergence and history of hybridization. This results in low morphological and genetic differences. This, coupled with low sampling and underdeveloped genetic techniques, has made taxonomy difficult to determine. Recent research using large genetic datasets has clarified these relationships into the groupings we recognize today.