Pinaceae have distinctive cones with woody scales bearing typically two ovules, and are supported as monophyletic by both morphological trait and genetic analysis.
[4] Major centres of diversity are found in the mountains of southwest China, Mexico, central Japan, and California.
Members of the family Pinaceae are trees (rarely shrubs) growing from 2 to 100 metres (7 to 300 feet) tall, mostly evergreen (except the deciduous Larix and Pseudolarix), resinous, monoecious, with subopposite or whorled branches, and spirally arranged, linear (needle-like) leaves.
The male cones are small, 0.5–6 cm (1⁄4–2+1⁄4 in) long, and fall soon after pollination; pollen dispersal is by wind.
Pines having seeds larger than 100 mg are more likely to have benefited from adaptations that promote animal dispersal, particularly by birds.
[5] Pinaceae that persist in areas where tree squirrels are abundant do not seem to have evolved adaptations for bird dispersal.
The narrow conical shape of northern conifers, and their downward-drooping limbs help them shed snow, and many of them seasonally alter their biochemistry to make them more resistant to freezing, called "hardening".
A more recent classification divided the subfamilies and genera based on the consideration of features of ovulate cone anatomy among extant and fossil members of the family.
Cedrus Pseudolarix Nothotsuga Tsuga Keteleeria Abies Pseudotsuga Larix Cathaya Picea Pinus Multiple molecular studies indicate that in contrast to previous classifications placing it outside the conifers, Gnetophyta may in fact be the sister group to the Pinaceae, with both lineages having diverged during the early-mid Carboniferous.
[14] Members of the modern genera Pinus (pines), Picea (spruce) and Cedrus (cedar) first appear during the Early Cretaceous.
[18] While Pinaceae, and indeed all of its subfamilies, substantially predate the break up of the super-continent Pangea, its distribution was limited to northern Laurasia.
During the Cenozoic, Pinaceae had higher rates of species turnover than Southern Hemisphere conifers, thought to be driven by range shifts in response to glacial cycles.
Common external stress that Pinaceae experience are herbivore and pathogen attack which often leads to tree death.
[30][28] Induced defense responses need to be activated by certain cues, such as herbivore damage or other biotic signals.
[27][33] It has been found that MJ stimulated the activation of PP cells and formation of xylem traumatic resin ducts (TD).