List of Pinus species
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 been further divided into sections based on chloroplast DNA sequencing and whole plastid genomic analysis. 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. The current division into two subgenera ("Pinus" and "Strobus") is supported with rigorous genetic evidence. Several features are used to distinguish the subgenera, sections, and subsections of pines: the number of leaves (needles) per fascicle, whether the fascicle sheaths are deciduous or persistent, the number of fibrovascular bundles per needle (2 in "Pinus" or 1 in "Strobus"), the position of the resin ducts in the needles (internal  or external), the presence or shape of the seed wings (absent, rudimentary, articulate, and adnate), and the position of the umbo (dorsal or terminal) and presence of a prickle on the scales of the seed cones. Both subgenera are thought to have a very ancient divergence from one another, having diverged during the late Jurassic. Subgenus "Pinus". Subgenus "Pinus" includes the yellow and hard pines. Pines in this subgenus have one to five needles per fascicle and two fibrovascular bundles per needle, and the fascicle sheaths are persistent, except in "P. leiophylla" and "P. lumholtzii". Cone scales are thicker and  more rigid than those of subgenus "Strobus", and cones either open soon after they mature or are serotinous. Section "Pinus". Section "Pinus" has two or three needles per fascicle. Cones of all species have thick scales, and all except those of "P. pinea" open at maturity. Species in this section are native to Europe, Asia, and the Mediterranean, except for "P. resinosa" in northeastern North America and "P. tropicalis" in western Cuba. Subsection "Pinus". All but two species (P. resinosa and P. tropicalis) in Subsection "Pinus" are native to Eurasia. Subsection "Pinaster". Subsection "Pinaster" contains species native to the Mediterranean , as well as "P. roxburghii" from the Himalayas. The scales of its cones lack spines. It is named after "P. pinaster". Section "Trifoliae". Section "Trifoliae" (American hard pines), despite its name (which means "three-leaved"), has two to five needles per fascicle, or rarely eight. The cones of most species open at maturity, but a few are serotinous. All but two American hard pines belong to this section. Phylogenetic analysis supports ancient divergences within this section, with subsections "Australes" and "Ponderosae" having diverged during the mid-Cretaceous. Subsection "Australes". Subsection "Australes" is native to North and Central America and islands  in the Caribbean. The closed-cone (serotinous) species of California and Baja California, "P. attenuata", "P. muricata", and "P. radiata", are sometimes placed in a separate subsection, "Attenuatae". Subsection "Contortae". Subsection "Contortae" is native to North America and Mexico. Subsection "Ponderosae". Subsection "Ponderosae" is native to Central America, Mexico, the western United States, and southwestern Canada. Subgenus "Strobus". Subgenus "Strobus" includes the white and soft pines. Pines in this subgenus have one to five needles per fascicle and one fibrovascular bundle per needle, and the fascicle sheaths are deciduous, except in "P. nelsonii", where they are persistent. Cone scales are  thinner and more flexible than those of subgenus "Pinus", except in some species like "P. maximartinezii", and cones usually open soon after they mature. Section "Parrya". Section "Parrya" has one to five needles per fascicle. The seeds either have articulate (jointed) wings or no wings at all. In all species except for "P. nelsonii", the fascicle sheaths curl back to form a rosette before falling away. The cones have thick scales and release the seeds at maturity. This section is native to the southwestern United States and Mexico. Subsection "Balfourianae". Subsection "Balfourianae (bristlecone pines) is native to southwest United States . Subsection "Cembroides". Subsection "Cembroides (pinyons or piñons) is native to Mexico and the southwestern United States. Subsection "Nelsonianae". Subsection "Nelsonianae" is native to northeastern Mexico. It consists of the single species with persistent fascicle sheaths. Section "Quinquefoliae". Section "Quinquefoliae" (white pines), as its name (which means "five-leaved") suggests, has five needles per fascicle except for "P. krempfii", which has two, and "P. gerardiana" and "P. bungeana", which have three. All species have cones with thin or thick scales that open at maturity or do not open at all; none are serotinous. Species in this section are found in Eurasia  and North America, and one species, "P. chiapensis" reaches Guatemala. Subsection "Gerardianae". Subsection "Gerardianae" is native to East Asia. It has three or five needles per fascicle. Subsection "Krempfianae". Subsection "Krempfianae" is native to Vietnam. It has two needles per fascicle, and they are atypically flattened. The cone scales are thick and have no prickles. Subsection "Strobus". Subsection "Strobus" has five needles per fascicle and thin cone scales with no prickles. Needles tend to be flexible and soft with slightly lighter side underneath. It is native to North and Central America, Europe, and Asia. Section::::"Incertae sedis". Species which are not  placed in a subgenus at this time.