There are three main subgenera of
Pinus, the subgenus
Strobus (
White pines or soft pines), the subgenus
Ducampopinus (
Pinyon,
Bristlecone and Lacebark pines), and the subgenus
Pinus (
Typical pines, or yellow or hard pines). This classification into the three subgenera is based on cone, seed and leaf characters
Notice that in many respects, subgenus Ducampopinus is intermediate between (and possibly ancestral to) the other two subgenera. In many classifications, it is combined into subgenus Strobus, but it could with equal justification have been included in subgenus Pinus (as was done in an early classification by the Californian botanist J G Lemmon in 1888), yet it does not sit comfortably in either so is best treated as a third subgenus in its own right. In general, cone and cone scale and seed morphology and leaf fascicle and sheath morphology are emphasized and this seems to result in a classification that has subsections of pines that are understandable and usually readily recognized by their general appearance. Pines with one fibrovascular bundle per leaf, i.e. subgenera Strobus and Ducampopinus, are known as haploxylon pines, while pines with two fibrovascular bundles per leaf, i.e. subgenus Pinus, are called diploxylon pines. Diploxylon pines tend to have harder timber and more amounts of resin than the haploxylon pines.
href="http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=3337" class="external text_related.html" title="http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=3337" rel="nofollow">NCBI Taxonomy server files Ducampopinus species above as Strobus.
