Strobus

Pinus, the Pines, is a genus of approximately 111 extant tree and shrub species. The genus is currently split into two subgenera: subgenus Pinus (hard pines), and subgenus Strobus (soft pines). Each of the subgenera have several sections within based on chloroplast DNA sequencing. Older classifications split the genus into three subgenera – subgenus Pinus, subgenus Strobus, and subgenus Ducampopinus (Pinyon, Bristlecone and Lacebark pines) – based on cone, seed and leaf characteristics. DNA phylogeny has shown that species formerly in subgenus Ducampopinus are members of subgenus Strobus, so Ducampopinus is no longer used.

The species of subgenus Ducampopinus were regarded as intermediate between the other two subgenera. In the modern classification, they are placed into subgenus Strobus, yet they did not fit entirely well in either so they were classified in a third subgenus. In 1888 the Californian botanist John Gill Lemmon placed them in subgenus Pinus. In general, this classification emphasized cone, cone scale, seed, and leaf fascicle and sheath morphology, and species in each subsection were usually recognizable by their general appearance. Pines with one fibrovascular bundle per leaf, (the former subgenera Strobus and Ducampopinus) were known as haploxylon pines, while pines with two fibrovascular bundles per leaf, (subgenus Pinus) were called diploxylon pines. Diploxylon pines tend to have harder timber and a larger amount of resin than the haploxylon pines.

Subgenus Pinus includes the yellow and hard pines.

Subgenus Strobus includes the white and soft pines.

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

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