Pinaceae

"The Pine Family"


Pinus strobus	Pseudotsuga menziesii
The Eastern White Pine	The Douglas Fir

The Pinaceae are resinous evergreen conifers, or cone-bearing trees, with needlelike leaves. They comprise about 9 genera and 225 speciesdistributed throughout the world, commonly in mountainous regions. They are endemic primarily to the temperate region of the northern hemisphere.

Click here for a distribution map of the Pinaceae in the U.S.A.

Vegetative Characters

Leaves are linear and needle-like, spirally disposed
Trees are almost all evergreen
Bark can be smooth to scaly or furrowed
Roots are fibrous to woody, unspecialized, and commonly with an ectomycorrhiza
Has woody cones which can be adjoined singly or in clusters, usually ovoid to ellipsiod or cylindric in shape

Reproductive Characters

Pollination occurs through wind
Male (mirosporangiate) strobili are small, terminal, or more often clustered along the stem axis, and consist of many papery microsporophylls each with two microsporangia on lower surface
Female cones (megasporangiate) strobili are woody and often large, consisting of many ovuliferous scales
Usually two seeds per scale and usually winged
In some species the cones open at maturity and release their seeds; in others the cones remain closed for several years until they are opened by rotting, by food-seeking animals, or by fire

Diagnostic Characters

Leaves are simple and sessile to short-petiolate
Usually aromatic
Usually male cones are located on the lower branches of the tree and female cones on the upper branches
Pines can be divided into two groups soft pines and hard pines based onthe way their needles grow, the structure of their cones, and the type of wood
Soft pines havesheathed needles that usually grow in groups of five but can appear in clustersof one to four
Soft pines usually have relatively soft and close-grained wood with little resin
Hard pines have sheathed needles that grow in clusters of two or three (in rare cases five to eight,) and the sheath remains attached to the base of teh cluster
The bracts on the cones of hard pines each have a prickle

Economic Importance/Fun Facts

Wide economic implication
Important source of timber, pulp turpentine, and resins
Seeds are edible
Cultivated ornamentals (think Christmas trees)
Pinus longaevais the oldest species
The Larix and Pseudolarix hae yearly deciduous leaves
The Pinus merkusii is the only species naturally found south of the equator

Evolutionary Adaptations and Relationships

Monophyletic group
Known in the fossil record since the mid-Jurasic period
Major environmental changes in the early Creatacious period led to a splitting into two subgenera Strobus and Pinus

Glossary of Terms

Deciduous - Trees which lose their leaves
Monoecious - organisms contain both male and female reproductive organs
Mycorrhiza - a fungus associated with the root of a plant, the association of mutual benefit
Resinous - containing a heavy, thick sap
Strobilus - a scaly, cone-like structure that bears spores

References and Links

http://www.botany.hawaii.edu/faculty/carr/pin.htm
http://www.wisc.edu/botit/systematics/phyla/coniferophyta/pinaceae.html
http://www.csdl.tamu.edu/FLORA/cgi/b98_map?family=PINACEAE
http://www.for.nau.edu/azproject/family/pin2.html
http://www.lovett-pinetum.org/4whatare.htm
http://www.ex.ac.uk/tours/conifers/pinaceae.html
http://treeguide.com/nn/family.asp?familyid=221andregion=northamerican
http://herkules.oulu.fi/isbn9514259246/html/x246.html

Pictures


Pinus strobus aril	Pinus contorta pollen grain


Abies balsamea and Tsuga canadensis	Larix decidua


Pinus strobus	Cross section of female cone

For questions or feedback, contact: Kris Hamwi