PINACEAE - TheBackCountry

PINACEAE

The Pinaceae (pine family) are trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, larches, pines, and spruces. The family is included in the order Pinales, formerly known as Coniferales.

Members of the family Pinaceae are trees (rarely shrubs) growing from 2 to 100 m (7 to 300 ft) tall, mostly evergreen (except the deciduous Larix and Pseudolarix), resinous, monoecious, with subopposite or whorled branches, and spirally arranged, linear (needle-like) leaves.

The female cones are large and usually woody, 2–60 cm (1–24 in) long, with numerous spirally arranged scales, and two winged seeds on each scale. The male cones are small, 0.5–6.0 cm (0.2–2 in) long, and fall soon after pollination; pollen dispersal is by wind. Seed dispersal is mostly by wind, but some species have large seeds with reduced wings, and are dispersed by birds. Analysis of Pinaceae cones reveals how selective pressure has shaped the evolution of variable cone size and function throughout the family. Variation in cone size in the family has likely resulted from the variation of seed dispersal mechanisms available in their environments over time. All Pinaceae with seeds weighing less than 90 mg are seemingly adapted for wind dispersal. Pines having seeds larger than 100 mg are more likely to have benefited from adaptations that promote animal dispersal, particularly by birds. Pinaceae that persist in areas where tree squirrels are abundant do not seem to have evolved adaptations for bird dispersal.

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