List of Pinus species

From Wikipedia, the free encyclopedia
  (Redirected from Strobus)
Jump to: navigation, search

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)[citation needed]. This classification into the three subgenera is based on cone, seed and leaf characters:

  • Subgenus Pinus Scale with a sealing band. Umbo dorsal. Seedwings articulate. Two fibrovascular bundles per leaf.
  • Subgenus Strobus Scale without a sealing band. Umbo terminal. Seedwings adnate. One fibrovascular bundle per leaf.
  • Subgenus Ducampopinus Scale without a sealing band. Umbo dorsal. Seedwings articulate. One fibrovascular bundle per leaf.

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.

Subgenus Pinus [edit]

Subgenus Pinus includes the yellow and hard pines.

Subgenus Strobus [edit]

Pinus strobus

Subgenus Strobus includes the white and soft pines.

Subgenus Ducampopinus [edit]

Subgenus Ducampopinus includes the Pinyon, Lacebark and Foxtail Pines.

Incertae sedis[edit]

Species which are not placed in a subgenus at this time.

References[edit]

  1. ^ Stockey, R.S. (1983). "Pinus driftwoodensis sp.n. from the early Tertiary of British Columbia". Botanical gazette 144 (1): 148–156. doi:10.1086/337355. 
  2. ^ McKown, A.D.; Stockey, R.A.; Schweger, C.E. (2002). "A New Species of Pinus Subgenus Pinus Subsection Contortae From Pliocene Sediments of Ch'Ijee's Bluff, Yukon Territory, Canada". International Journal of Plant Sciences 163 (4): 687–697. doi:10.1086/340425. 

External links[edit]