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Illustrated key of compound-leaved trees |
back to main tree key hickory key sumac key
(Modified from a text key to common trees of Radnor Lake by W.G. Eickmeier)
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1. Leaves with 3 leaflets, shrubs or small
trees:
go to 2
1. Leaves with more than 3 leaflets, may be large trees: go to 3
2. Leaves opposite and with no strong smell,
fruit an inflated baglike capsule:
Staphylea trifolia (American bladdernut)
2. Leaves alternate and having a strong, fragrant smell, fruit a red
drupe:
Rhus aromatica (fragrant sumac)
3. Leaves pinnately compound:
go
to 4
3. Leaves palmately compound:
Aesculus
flava
(yellow buckeye)
4. Leaves alternate:
go
to 5
4. Leaves opposite:
go
to 15
5. Some or all leaves twice
compound (bipinnate): go to 6
5. Leaves only once compound:
go
to 9
6. Trunks or branches with spines or prickles:
go to 7
6. Trunks and branches without spines or prickles: go
to 8
7. Enormous leaves that are always
twice pinnate, leaf petioles usually with
prickles, usually a small tree and often a single unbranched stem, prickles
relatively short, fruit a purple-black drupe (one-seeded fleshy fruit) in a
large terminal panicle:
Aralia
spinosa
7. Leaves may be twice pinnate and once pinnate on the same tree, leaf
petioles without prickles, can be a large tree, stout branched thorns
often present, legume relatively thin and leathery, about 30 cm long:
Gleditsia
triacanthos (honey locust)
8. Leaflets small and
symmetric, fruit a relatively thin legume, non-native escaped species:
Albizia
julibrissin
8. Leaflets large and asymmetric, fruit a large woody legume, not
common in the wild, but often planted:
Gymnocladus
dioicus (Kentucky coffeetree)
9. Lateral buds hidden under
hollow petiole base, fruit a legume: go to
10
9. Lateral buds evident and axillary, fruit
not a legume: go to 12
10. Leaflets small, about 3
cm long, elliptical, twigs may have visible spines or prickles: go to 11
10. Leaflets large, about 5 to 10 cm long,
leaflets alternate on rachis and ovate, twigs without visible spines or
prickles, bark light gray and smooth:
11. Leaflet margin without
teeth, node usually with a pair of spines, bark deeply furrowed, furrows often
with orange tinge, legume small, about 5 cm:
Robinia
pseudoacacia (black
locust)
11. Leaflet margin with teeth, twigs usually
with simple or branched thorns, legume about 30 cm long (leaves may be twice
pinnate and once pinnate on the same tree):
Gleditsia
triacanthos (honey locust)
12. Leaves with 5 or more pairs of lateral leaflets:
go to 13
12. Leaves with mostly fewer than 4 pairs of
lateral leaflets: go to key of
hickories
13. Sap milky, fruit a red or brown berrylike fruit,
a small tree or bush: go to key of sumacs
13. Sap not milky, fruit winged or a nut and not berrylike, may be a
large tree: go to 14
14. Terminal leaflet present,
fruit a samara, bark light gray and thin with distinctive pattern, leaflets with
glands at base, leaves somewhat malodorous:
Ailanthus
altissima
(tree of
heaven)
14. Terminal leaflet often absent, fruit a
nut, bark dark with prominent V-shaped furrow, pith of small twigs chambered:
Juglans
nigra
(black walnut)
15. Leaflets 3-5, twigs
green, fruit a double samara:
Acer
negundo
(box elder)
15. Leaflets 7-11, twigs not green, fruit a
single samara: go to 16
16. Bark prominently
diamond patterned, diamonds 3 to 5 cm long, twigs not angled or winged near tip:
Fraxinus
americana
16. Bark divided into plate-like scales,
twigs 4-angled to 4-winged most obviously near tips:
Fraxinus
quadrangulata
(blue
ash)