Pinaceae

Intermountain Flora, v. 1, p. 223

• 1. Leaves borne on more or less elongated branchlets, spirally arranged, never fascicled; ovulate cones maturing the first season.
• 2. Leaves more or less quadrangular in cross section; cones pendulous, 4-10 cm long, with persistent scales exceeding the bracts; spruces. Picea
• 2.1. Young twigs usually pubescent; cones usually 4-6-(7.5) cm long; needles not especially sharp to the touch; bark of mature trees thin and scaly. Picea engelmannii

Picea engelmannii	Picea engelmannii	Picea engelmannii

• 2.1' Young twigs glabrous; cones usually 6-10 cm long; needles very sharp to the touch; bark of mature trees becoming thick and furrowed. Picea pungens

Picea pungens	Picea pungens	Picea pungens

• 2' Leaves evidently somewhat flattened in cross section; cones not wholly as above; firs.
• 3. Cones pendulous, their scales persistent, the bracts excerted and conspicuous; leaves narrowed at the base, sometimes shortly petiolate, the point of attachment less than 1 mm wide (0.3-0.9 mm); winter buds reddish-brown, sharp pointed. Pseudotsuga menziesii

Pseudotsuga menziesii	Pseudotsuga menziesii	Pseudotsuga menziesii

• 3' Cones erect, their scales decidious, the bracts consealed by the scales; leaves more or less carrying their width to the base, the point of attachment at least 1 mm wide (1.0-2.4 mm); winter buds brown, blunt, dull. Abies
• 3'1. Resin ducts (when viewed in cross section) nearest the lower epidermis towards the margins, usually small; leaves of the lower branches 3-6 cm long; 1 year-old twigs glabrous; ovulate cones grayish- to yellowish-green. Abies concolor var. concolor

Abies concolor	Abies concolor	Abies concolor

• 3'1' Resin ducts mediantly located between the upper and lowers epidermis and between the leaf margin and the midvein, usually large; leaves of the lower branches 2-3 cm long; 1 year-old twigs pubescent; ovulate cones dark brown-purple. Abies bifolia var. bifolia = Abies lasiocarpa var. lasiocarpa

Abies lasiocarpa	Abies lasiocarpa	Abies lasiocarpa	Abies lasiocarpa

• 1' Leaves borne in fascicles of 2-5 (solitary in P. monophylla) on short spur-like branches, each fascicle surrounded at the base by a papery sheath (at least when young); ovulate cones (ours) maturing the second season. Pinus
• 1'1. Leaves 5 to a fascicle; position of the umbo various.
• 1'2. Ovulate cone scales with a terminal unarmed umbo; leaves (3)-3.5-10 cm long; section Strobus, the white pines.
• 1'3. Ovulate cones 2.5-12-(25) cm long, broad, short-stalked to subsessile, the stalk less than 1 cm long; leaves 3-7-(8) cm long, entire; generally distributed in our range.
• 1'4. Ovulate cones small, only 2.5-7 cm long, the scales remaining closed at maturity, very thick at the apex; mountains of W and N Nevada. Pinus albicaulis

Pinus albicaulis	Pinus albicaulis

• 1'4' Ovulate cones larger, 7-12-(25) cm long, the scales spreading apart at maturity, not very thick at the apex; mountains throughout all but the NW corner of our region. Pinus flexilis

Pinus flexilis	Pinus flexilis

• 1'3' Ovulate cones (10)-15-50 cm long, narrow oblong, long-stalked, the stalk 1-8 cm long; leaves mostly longer, 5-10 cm long, often minutely serrulate-margined; barely, if at all, entering our range in W Nevada, near Reno.
• 1'5. Ovulate cones 25 cm long or less; leaves without conspicuous white lines on back. Pinus monticola

Pinus monticola	Pinus monticola

• 1'5' Ovulate cones 30 cm long or more; leaves with conspicuous white lines on back; approaching on the west but not known from our area. Pinus lambertiana

Pinus lambertiana	Pinus lambertiana	Pinus lambertiana

• 1'2' Ovulate cone scales with a dorsal umbo, armed with a spine; leaves short, 2-4 cm long; section Parrya. Pinus longaeva

Pinus longaeva	Pinus longaeva

• 1'1' Leaves 1-3 to a fascicle; ovulate cone scales with a dorsal umbo.
• 1'6. Mature trees round-topped, mostly less than 15 m high; seeds with very narrow wing; leaves short, 2-5-(6) cm long; section Parrya; the pinnions or nut pines.
• 1'7. Leaves 2-(3) to a fascicle; chiefly in the Colorado Plateau region. Pinus edulis

Pinus edulis	Pinus edulis	Pinus edulis	Pinus edulis

• 1'7' Leaves usually solitary, terete; chiefly in the Great Basin region, to the west of the range of P. edulis. Pinus monophylla

Pinus monophylla	Pinus monophylla	Pinus monophylla

• 1'6' Mature trees forming a pyramidal head, more than 20 m high; seeds prominently winged; leaves (except in P. contorta) well over 5 cm long; section Pinus.
• 1'8. Leaves mostly 3 to a fascicle (occasionally 2), relatively long, (7)-9-30 cm; ovulate cones 15-25 cm long, symmetrical.
• 1'9. Ovulate cones 7-15 cm long, the scales with a prickle turned outward; buds with resin droplets; somewhat widespread in our region. Pinus ponderosa / Pinus brachyptera

Pinus ponderosa	Pinus ponderosa

• 1'9' Ovulate cones 15-35 cm long, the scales with a prickle turned inward; buds without resin droplets; extreme W Nevada and adjacent California. Pinus jeffreyi

Pinus jeffreyi	Pinus jeffreyi	Pinus jeffreyi

• 1'8' Leaves mostly 2 to a fascicle, relatively short, 2.5-7-(8.5) cm long; ovulate cones 3-6 cm long, usually slightly lopsided. Pinus contorta

Pinus contorta	Pinus contorta	Pinus contorta	Pinus contorta

Extended key to Pinus

http://arnoldia.arboretum.harvard.edu/pdf/articles/1951-11--simple-key-to-the-pines.pdf

• 1a. Needles 5 in a sheath.
• 2a. Needles usually less than 37 mm long with smooth margin (California to Colorado; zone 5). Pinus aristata

Pinus aristata

• 2b. Needles usually 37-50 mm long.
• 3a. Bark of trunk brown to creamy white; needles rigid and stout, margin smooth (British Columbia to California; zone 3). Pinus albicaulis
• 3b. Bark of trunk black; needles more flexible.
• 4a. Needles bluish green, often twisted, intensely white underneath; leaf margin finely serrulate, i.e. rough to the touch (Japan; zone 5). Pinus parviflora
• 4b. Needles intensely bluish green. Pinus parviflora glauca
• 4c. Needles light green, not twisted.
• 5a. Mature twigs glabrous, needles smooth (Alberta to California; zone 4). Pinus flexilis
• 5b. Mature twigs pubescent; leaf margin finely serrulate, i.e., rough to the touch (Japan; zone 3). Pinus pumila
• 2c. Needles mostly 6-11 cm long; leaf margin serrulate, rough to the touch.
• 6a. Mature twigs glabrous.
• 7a. Plant shrubby, not tree-like. Pinus strobus nana
• 7b. Branches unright; tree dense.
• 8. Needles stiff (Balcan Mountains; zone 4) Pinus peuce
• 8' Needles soft and flexible. Pinus strobus fastigata

Pinus strobus

• 7c. Branches horizontal; tree more open.
• 9. Cones usually 50-120 mm long; twigs glabrous or only slightly pubescent (Eastern US and Canada; zone 3). Pinus strobus
• 9' Cones usually 115-250 mm long; twigs pubescent when young (British Columbia to Idaho and California; zone 5). Pinus monticola
• 6b. Mature twigs pubescent.
• 10. Tree densely upright, pyramidal in habit. Pinus cembra
• 10' Tree not as above, more open.
• 11. Needles lustrous, dark green (Japan, Korea; zone 3). Pinus koraiensis
• 11' Needles dull green.
• 12. Terminal bud blunt almost globular, cones 30-50 cm (Oregon to California; zone 5). Pinus lambertiana
• 12' Terminal bud sharply pointed, definitely not globular; cones 10-25 cm (British Columbia to Idaho and California; zone 5). Pinus monticola
• 2d. Needles 11-20 cm long. Pinus griffithi
• 2e. Needles 20-30 cm long. Pinus torreyana
• 1b. Needles 3-4(5); leaf margin smooth (California; zone 9). Pinus cembroides parryana
• 1c. Needles 3 in a sheath.
• 13a. Needles mostly 5-11 cm long.
• 14. Leaf sheaths decidious; bark of older twigs smooth, bark of trunk flaky with white or yellow patches (China; zone 4). Pinus bungeana
• 14' Leaf sheaths not decidious; bark of older twigs very rough, bark of trunk dark brown to black.
• 15. Foliage dark green; cones usually 5-10 cm long (Eastern US and Canada; zone 4). Pinus rigida
• 15' Foliage bright or bluish green; cones usually 7.5-17.5 cm long.
• 16. Bark on upper part of trunk and branches smooth (Oregon to California; zone 8). Pinus attenuata
• 16' Bark on upper part of trunk and branches rough (southern California; zone 8). Pinus radiata
• 13b. Needles mostly 11-25 cm long.
• 17. Winter buds resinous.
• 18. Twigs fragrant when broken; cones 7.5-15 cm; foliage dark green; branchlets orange brown (eastern and central US; zone 5). Pinus ponderosa
• 18' Twigs not fragrant when broken; cones 23-45 cm; foliage bluish green (Callifornia; zone 8). Pinus coulteri
• 17' Winter buds not resinous.
• 19. Foliage bluish green.
• 20. Needles stout; bark cinnamon red; cones 15-30 cm (Oregon and California; zone 5). Pinus jeffreyi
• 20' Needles slim; bark red brown; cones 7-15 cm (New Jwrsey to Florida and Texas; zone 6). Pinus taeda
• 19' Foliage dark green; cones 7-30 cm (California; zone 8). Pinus coulteri
• 13c. Needles 20-45 cm long.
• 21. Foliage gray bluish green.
• 22. Needles slender, drooping (California; zone 6). Pinus sabiniana
• 22' Needles stiff, erect (Callifornia; zone 8). Pinus coulteri
• 21' Foliage green.
• 23. Needles mostly 20-25 cm long, light green and lustrous (Canary Islands; zone 10?). Pinus canariensis
• 23' Needles mostly 30 cm or more long, dark green (southeastern US; zone 7). Pinus palustris
• 1d. Needles 3 and 2 in a sheath.
• 24a. Needles less than 5 cm long (southern California and Arizona; zone 9). Pinus cembroides
• 24b. Needles more than 5 cm long.
• 25a. One year twigs greenish to purplish, covered with glaucous bloom (eastern US; zone 5). Pinus echinata
• 25b. One year twigs yellow brown to brownish.
• 26a. Terminal bud very resinous (Rocky Mountain region; zone 4). Pinus ponderosa scopulorum
• 26b. Terminal bud not resinous or only slightly so.
• 27a. Needles 5-17 cm long; cones 3-5 cm long (China; zone 5). Pinus tubulaeformis
• 27b. Needles 20-30 cm long; cones 7-16 cm long (southeastern US, Bahamas, Honduras; zone 8). Pinus caribaea
• 1e. Needles 2 in a sheath.
• 28a. Needles 2-4 cm long.
• 29a. Foliage with each needle marked with a yellow band. Pinus densiflora oculus-draconis

Pinus densiflora oculus-draconis

• 29b. Foliage bluish green; bark of upper trunk red (Europe; zone 2). Pinus sylvestris

Pinus sylvestris	Pinus sylvestris	Pinus sylvestris	Pinus sylvestris

• 29c. Foliage green.
• 30a. Plant usually shrubby, with several main branches from the base.
• 31a. Needles 2-5 cm long; bark black (central Europe; zone 2). Pinus mugo

Pinus mugo

• 32a. Dense, almost globose shape. Pinus mugo compacta

Pinus mugo compacta

• 32b. Shrubby, upright habit. Pinus mugo pumilo

Pinus mugo pumilo	Pinus mugo pumilo

• 31b. Needles 3-7.5 cm; bark red to reddish. Pinus densiflora umbraculifera

Pinus densiflora umbraculifera	Pinus densiflora umbraculifera

• 30b. Plant a tree with a central leader.
• 33a. Needles mostly 2.5 cm long. Pinus banksiana

Pinus banksiana	Pinus banksiana

• 33b. Needles mostly 3-7.5 cm long.
• 34a. Branchlets usually with glaucous bloom, often greenish to purplish or yellowish.
• 35a. Foliage bluish green; cones usually not persistent; bark of upper trunk red; leaves flexible (Japan; zone 4). Pinus densiflora

Pinus densiflora	Pinus densiflora

• 35b. Foliage bright green; cones persistent; bark of upper trunk black; leaves stiff (eastern US; zone 4). Pinus virginiana
• 34b. Branchlets without glaucous bloom, orange to yellow.
• 36a. Vigorous shoots often with more than one whorl of branches on the current year's growth (southeastern US; zone 5). Pinus pungens

Pinus pungens	Pinus pungens	Pinus pungens

• 36b. Vigorous shoots often with only one whorl of branches on the current year's growth
• 37a. Winter buds white or whitish to light yellow (Japan; zone 4). Pinus thunbergi

Pinus thunbergi	Pinus thunbergi

• 37b. Winter buds dark brown (China; zone 5). Pinus tabulaeformis

Pinus tabulaeformis

• 28b. Needles 4-20 cm long.
• 38a. Winter buds resinous.
• 39a. Needles slender and flexible, breaking when bent. Pinus resinosa
• 39b. Needles stout and stiff, not breaking when bent (central Europe; zone 4). Pinus nigra austriaca
• 38b. Winter buds not resinous, or only slightly so (in Pinus tabulaeformis).
• 40a. Buds stout, up to 2.5 cm long; branchlets reddish brown (Portugal to Greece; zone 8). Pinus pinaster
• 40b. Buds less than 1.3 cm long.
• 41a. Bark of upper trunk red (Japan; zone 4). Pinus densiflora
• 41b. Bark of upper trunk black.
• 42a. One year twigs with glaucous bloom, green to purplish (eastern US; zone 5). Pinus echinata
• 42b. One year twigs without glaucous bloom, yellow to brown.
• 43a. Winter buds dark reddish brown (China; zone 5). Pinus tabulaeformis
• 43b. Winter buds light yellow to white or whitish (Japan; zone 4). Pinus thunbergii