Resources
Dichotomous Keys - Text Format
Conifer Key

Tips: Select a twig that seems typical of the tree. Try to obtain a twig with reproductive structures (fruits, cones) because you may need to observe them to identify your tree. This key is for conifers (trees which have leaves that look like needles or tiny overlapping scales, are frequently evergreen, lack flowers, usually bear woody or leathery cones, and produce seeds). To use the key, read both descriptions in a couplet (for instance, 1a and 1b). Decide which best describes your sample, and move on to the next couplet indicated. Should you reach a dead-end, use the numbers in parentheses to backtrack until you reach a couplet that you feel unsure about, and try following the other path. Some tree genera are found more than once in the key because they occur with different forms. Only trees which are native to the United States are included in this key.

Trees with needles or overlapping scales:
STEP FROM FEATURES GENUS
1a Trees with needles. . . . . . . . . go to 2
1b Trees with at least some tiny overlapping scales. . . . . . . . . . go to 13
2a 1a Trees with fleshy, berry-like fruits. . . . . . . . . . go to 3
2b 1a Trees with woody cones. . . . . . . . . . go to 5
3a 2a Each bright red fruit partially covers a black seed
TAXUS
(Yew)
3b 2a Each fruit totally encloses the seed. . . . . . . . . . go to 4
4a 3b Oval green-purple fruits with a diameter of approximately 25 mm
TORREYA
4b 3b Globe-like blue-black fruits with a diameter of approximately 10 mm
JUNIPERUS
(Juniper)
5a 2b Groups of needles are attached to the twigs in clusters. . . . . . . . . . go to 6
5b 2b Single needles are attached to the twigs. . . . . . . . . .go to 7
6a 5a Clusters of 2 - 5 needles
PINUS
(Pine)
6b 5a Clusters of 12 - 50 soft needles
LARIX
(Larch)
7a 5b Cones stand up from the upper side of the twig
ABIES
(Fir)
7b 5b Cones hang down from the lower side or end of the twig. . . . . . . . . .go to 8
8a 7b Cones have long, pointy bracts extending beyond scales
PSEUDOTSUGA
(Douglas fir)
8b 7b Cones don’t have long, pointy bracts or scales. . . . . . . . . .go to 9
9a 8b Each needle is tucked into a papery sheath
PINUS
(Singleleaf pinyon)
9b 8b Needles are not tucked into papery sheaths. . . . . . . . . . go to 10
10a 9b Cones attached along the length of the twig, trees often found in swamps, with root "knees"
TAXODIUM
(Baldcypress)
10b 9b Cones hang at the ends of twigs, without root "knees". . . . . . . . . . go to 11
11a 10b Needles attached to twigs by little woody projections. . . . . . . . . . go to 12
11b 10b Needles attached directly to stems without woody projections
SEQUOIA
(Coastal redwood)
12a 11a Needles are four-sided and stiff with sharp tips
PICEA
(Spruce)
12b 11a Needles are flat and flexible with blunt tips
TSUGA
(Hemlock)
13a 1b Trees with fleshy, berry-like fruits
JUNIPERUS
(Juniper)
13b 1b Trees with woody or leathery cones. . . . . . . . .go to 14
14a 13b Alternated leaf scales, cones 40mm - 80 mm long with numerous, spirally arranged scales
SEQUIOADENDRON
(Giant Sequoia)
14b 13b Leaf scales opposite or whorled, cones 40 mm long with only a few opposite scales. . . . . . . . . . go to 15
15a 14b Globe-shaped cones. . . . . . . . . .go to 16
15b 14b Cones are longer than they are wide. . . . . . . . . .go to 17
16a 15a Twigs form flattened cones 13 mm in diameter with 2 - 5 seeds per cone scale
CHAMAECYPARIS
(False Cypress)
16b 15a Twigs do not form flattened "sprays", cones 13 mm - 40 mm in diameter with > 5 seeds per cone scale
CUPRESSUS
(Cypress)
17a 15b Leaf scales are mostly long, narrow and pointed, seed-bearing cones are urn-ashaped with rigid scales
CALOCEDRUS
(Incense cedars)
17b 15b Leaf scales are mostly short and broad with blunt tips, seed-bearing cones are oval with flexible scales
THUJA
(Arborvitae)



Back to Resource page