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Winter Twig Identification Key

This random access identification key covers 67 species of Washington's deciduous trees, shrubs, and vines - including most of the common species - using characteristics of the twigs, buds, and bark that are visible during the winter, with supplementary characters for leaves and fruits that frequently persist on the plant or on the ground beneath.

To use this key, compare a twig sample against the characteristics given below and then select those characteristics that best match the sample. Click the Show Matches button to view a list of the species that match the selected characteristics. Characteristics are organized into categories, and within each category only one selection can be made. If you are uncertain which character to select within a category you are better off leaving that category blank.

Funding for the development of this key and the acquisition of photos was provided by an anonymous donation. Key data was compiled from examination of twig specimens and technical floras by Ben Legler.


Bud and leaf arrangement:
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  Buds and leaves alternate
  Buds and leaves opposite
  Buds and leaves whorled (3 or more per node)

Bud tip shape:
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  Bud tips pointed
  Bud tips rounded

Bud scale arrangement:
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  Scales covering bud imbricate (overlapping like shingles)
  Scales covering bud valvate (2 scales closing like a clam shell)
  Only a single scale covering entire bud
  Bud scales absent

Bud scale pubescence:
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  Bud scales pubescent or ciliate-margined
  Buds scales with glandular or punctate dots or scales
  Buds scales glabrous

Bud resin:
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  Resin present on bud surface (sticky, waxy, or varnish-like coating)
  Resin absent from bud surface (surface shiny or not)

Primary Bud color:
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  Green or yellow
  Red or maroon, or strongly tinged with such
  Brown or tan (no red or green tinge)
  Gray, light or dark

Thorns or spines:
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  Stems armed with thorns, spines, or prickles
  Stems lacking thorns, spines, or prickles

Twig cross-section (first year twigs):
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  Twigs round in cross-section
  Twigs square in cross-section
  Twigs angled in cross-section

Primary Twig color (first year twigs):
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  Red or maroon, or strongly tinged with such
  Brown or tan (no red or green tinge)
  Gray, white or black

Twig pith (spongy tissue inside twig):
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  Pith absent, twigs woody throughout
  Pith present but not chambered
  Pith present and chambered at least in center

Twig pubescence (first year twigs):
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  Twigs pubescent
  Glands or puncate dots present on twigs
  Twigs entirely glabrous

Vascular bundles on leaf scars:
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  Bundles not visible
  Bundles 1 per leaf scar
  Bundles 3 per leaf scar
  Bundles > 3 per leaf scar

Bark color (main trunk or basal stems):
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  Red or maroon, or strongly tinged with such
  Brown or tan (no red or green tinge)
  Gray, light (white) or dark

Bark texture (main trunk or basal stems):
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  Papery and often peeling
  Fibrous, in longitudinal strips
  Furrowed or fissured

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  Tree (> 4 meters tall, trunk > 10 cm diameter, mostly single stemmed)
  Shrub (< 4 meters tall, stems < 10 cm diameter, or multi-stemmed)
  Vine (climbing upon other plants or trailing across ground)

Range in Washington:
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  Western Washington (west of the Cascade Crest)
  Eastern Washington (east of the Cascade Crest)

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  Forested areas at low-mid elevation
  Subalpine/alpine forest, meadow, or rocky slopes
  Prairie or rocky bald in Western WA
  Sagebrush-steppe, desert, or grassland in Eastern WA
  Freshwater wetland, bog, lake, river, or stream
  Saltwater beach, marsh, or coastal dunes
  Disturbed area: field, roadside, wastelot, town

Leaf type:
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  Simple (including deeply lobed leaves)
  Ternately compound
  Pinnately compound
  Palmately compound

Leaf veins:
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  Veins not visible
  Veins pinnate
  Veins palmate
  Veins parallel

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  Catkins or woody cones
  Racemes or spikes
  Branched clusters
  Flowers and fruits solitary
  Flowers and strictly paired

Fruit/seed type:
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  Fleshy (berry, drupe, rosehip, ...)
  Nut, with hard woody shell
  Dry, prominently winged (maple key, samara)
  Dry, not winged (achene, capsule, utricle, ...)

Fruit/seed color (when fresh):
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  Black or dark gray
  Brown or tan
  Red, orange, or yellow
  Blue or purple


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