Hybridization in pines explained

Both naturally and artificially occurring pine species (Pinus) can hybridize, combining their genetic material and sometimes creating hybrids that can be more or less vigorous than their parent species. An example of a naturally occurring hybrid pine is Pinus × sondereggeri, a naturally occurring cross between loblolly pine (P. taeda) and longleaf pine (P. palustris). An example of the many artificial hybrids is Pinus lambertiana × P. armandii.^[1]

Subgenus Pinus

Includes both natural and artificial pine hybrids.

Subsection Pinus

• Pinus nigra × P. resinosa – Austrian pine × red pine
• Pinus densiflora × P. nigra^[2] – Japanese Red pine × Austrian pine
• Pinus × densithunbergii, Pinus densiflora × P. thunbergii^[3] – Japanese Red pine × Japanese black pine
• Pinus × neilreichiana, Pinus nigra × P. sylvestris^[4] – Neilreich pine (Austrian pine × Scots pine)
• Pinus × rhaetica, Pinus mugo × P. sylvestris – Rhætic pine (Mountain pine × Scots pine)

Subsection Ponderosae

• Pinus ponderosa var. ponderosa × P. arizonica – Ponderosa pine (typical variety) × Arizona pine
• Pinus ponderosa var. ponderosa × P. montezumae – Ponderosa pine (typical variety) × Montezuma pine
• Pinus ponderosa var. scopulorum × P. montezumae – Rocky Mountain ponderosa pine × Montezuma pine
• Pinus engelmannii × P. montezumae – Apache pine × Montezuma pine
• Pinus jeffreyi × P. montezumae – Jeffrey pine × Montezuma pine
• Pinus ponderosa var. ponderosa × P. engelmannii – Ponderosa pine (typical variety) × Apache pine
• Pinus engelmannii × P. arizonica – Apache pine × Arizona pine
• Pinus engelmannii × P. ponderosa var. scopulorum – Apache pine × Rocky Mountain ponderosa pine
• Pinus jeffreyi × P. ponderosa var. ponderosa – Jeffrey pine × ponderosa pine (typical variety)
• Pinus jeffreyi × P. ponderosa var. scopulorum – Jeffrey pine × Rocky Mountain ponderosa pine
• Pinus jeffreyi × P. ponderosa var. washoensis – Jeffrey pine × Washoe pine
• Pinus. ponderosa var. washoensis × P. ponderosa var. ponderosa – Washoe pine × ponderosa pine (typical variety)
• Pinus. ponderosa var. washoensis × P. ponderosa var. scopulorum – Washoe pine × Rocky Mountain ponderosa pine
• Pinus jeffreyi × P. coulteri – Jeffrey pine × Coulter pine

Subsection Contortae

• Pinus × murraybanksiana, Pinus contorta var. murrayana × P. banksiana – Murraybanks pine (Sierra lodgepole pine × jack pine)
• Pinus contorta var latifolia × P. banksiana – Rocky Mountain Lodgepole Pine × Jack Pine
• Pinus virginiana × P. clausa – Virginia pine × Sand pine

Subsection Australes

• Pinus × sondereggeri, Pinus palustris × P. taeda – Sonderegger's pine (Longleaf pine × loblolly pine)
• Pinus elliottii × P. palustris – Slash pine × longleaf pine
• Pinus elliottii × P. taeda – Slash pine × loblolly pine
• Pinus echinata × P. elliottii – Shortleaf pine × slash pine
• Pinus echinata × P. taeda – Shortleaf pine × loblolly pine
• Pinus pungens × P. echinata – Table Mountain pine × shortleaf pine
• Pinus rigida × P. echinata – Pitch pine × shortleaf pine
• Pinus x rigitaeda, Pinus rigida × P. taeda – Pitlolly pine (Pitch pine × loblolly pine)

• Pinus rigida × P. serotina – Pitch pine × pond pine
• Pinus patula × P. greggii – Mexican weeping pine × Gregg pine
• Pinus patula × P. radiata – Mexican weeping pine × Monterey pine
• Pinus attenuata × P. radiata – KMX pine (Knobcone pine × Monterey pine)
• Pinus attenuata × P. muricata – Knobcone pine × bishop pine

Subgenus Strobus

Includes both natural and artificial pine hybrids. There have been external reports of pine hybrids in the subgenus Strobus.^[5]

Subsection Cembroides

• • Pinus quadrifolia × P. monophylla subsp. californiarum^[6] – Parry pinyon × California single-leaf pinyon Pinus quadrifolia × P. monophylla – Parry pinyon × single-leaf pinyon
• Pinus monophylla × P. edulis – Single-leaf pinyon × Colorado pinyon

Subsection Strobus

• Pinus pumila × P. sibirica^[7] – Japanese stone pine × Siberian pine
• Pinus × hakkodensis, Pinus parviflora var. pentaphylla × P. pumila^[8] – Hakkoda pine (Japanese white pine × Japanese stone pine)
• Pinus × holfordiana, Pinus ayacahuite × P. wallichiana^[9] – Holford pine (Mexican white pine × Himalayan pine)
• Pinus × hunnewellii, Pinus parviflora × P. strobus^[10] – Hunnewell's white pine (Japanese white pine × eastern white pine)
• Pinus monticola × P. parviflora – Western white pine × Japanese white pine
• Pinus lambertiana × P. armandii – Sugar pine × Armand pine
• Pinus lambertiana × P. koraiensis – Sugar pine × Korean pine
• Pinus monticola × P. strobiformis – Western white pine × southwestern white pine
• Pinus monticola × P. flexilis – Western white pine × limber pine
• Pinus monticola × P. strobus – Western white pine × eastern white pine
• Pinus monticola × P. peuce – Western white pine × Balkan pine
• Pinus peuce × P. strobus – Balkan pine × eastern white pine
• Pinus peuce × P. parviflora – Balkan pine × Japanese white pine
• Pinus flexilis × P. wallichiana – Limber pine × Himalayan pine
• Pinus flexilis × P. strobus^[11] – Limber pine × eastern white pine
• Pinus flexilis × P. ayacahuite – Limber pine × Mexican white pine
• Pinus ayacahuite × P. strobus – Mexican white pine × eastern white pine
• Pinus × schwerinii, Pinus strobus × P. wallichiana – Schwerin's white pine (Eastern white pine × Himalayan pine)
• Pinus monticola × P. wallichiana – Western white pine × Himalayan pine
• Pinus cembra × P. sibirica – Swiss stone pine × Siberian pine
• Pinus cembra × P. albicaulis – Swiss stone pine × whitebark pine
• Pinus albicaulis × P. flexilis – Whitebark pine × limber pine
• Pinus sibirica × P. cembra – Siberian pine × Swiss stone pine
• Pinus sibirica × P. koraiensis – Siberian pine × Korean pine
• Pinus armandii × P. koraiensis – Armand pine × Korean pine
• Pinus strobus × P. ayacahuite^[12] – Eastern white pine × Mexican white pine

Notes and References

1. Web site: Botanical descriptions of 40 artificial pine hybrids .
2. Web site: Pinus densiflora x nigra / Japanese red-Austrian black pine hybrid Conifer Species . 2022-03-23 . American Conifer Society . en.
3. Web site: Pinus × densithunbergii / hybrid pine Conifer Species . 2022-03-23 . American Conifer Society . en.
4. Web site: Pinus × neilreichiana / Neilreich pine Conifer Species . 2022-03-23 . American Conifer Society . en.
5. Web site: sjgbloom2012 . 2015-08-04 . Pinus armandii x P. koraiensis • Korean Pine . 2022-03-22 . SJG bloom . en.
6. Patterns of hybridization and cryptic introgression among one- and four-needled pinyon pines . 2022-03-25 . Annals of Botany. 13 August 2020 . 126 . 3 . 401–411 . 10.1093/aob/mcaa045 . Buck . Ryan . Hyasat . S. . Hossfeld . A. . Flores-Rentería . L. . 32222765 . 7424738 .
7. Web site: Goroshkevich . Sergej N. . Natural Hybridization between Russian Stone Pine (Pinus siberica) and Japanese Stone Pine (Pinus pumila) . 2022-03-24 . US Forest Service . 2004 . en.
8. Web site: Pinus × hakkodensis / Hakkoda pine Conifer Species . 2022-03-23 . American Conifer Society . en.
9. Web site: Pinus × holfordiana / Holford pine Conifer Species . 2022-03-23 . American Conifer Society . en.
10. Web site: Pinus × hunnewellii / Hunnewell's white pine Conifer Species . 2022-03-23 . American Conifer Society . en.
11. Critchfield . William B. . 1986 . Hybridization and classification of the white pines (Pinus section strobus) . Taxon . 35 . 4 . 647–656 . 10.2307/1221606 . 1221606 . en.
12. Web site: Pinus strobus × ayacahuite / hybrid pine Conifer Species . 2022-03-23 . American Conifer Society . en.