Jepson eFlora: Taxon page
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Thuja plicata

Higher Taxonomy
Family: CupressaceaeView DescriptionDichotomous Key

Habit: Shrub, tree, generally evergreen; monoecious or dioecious. Leaf: simple, cauline, alternate or opposite (either +- 4-ranked) or whorled in 3s (6-ranked), linear or scale-, awl- or needle-like (sometimes linear and awl-like on 1 pl, or on juvenile or injured plants), generally decurrent, covering young stems. Pollen Cone: axillary or terminal. Seed Cone: +- fleshy to generally woody, generally hard at maturity; scales opposite or whorled, peltate or not. Seed: 1--many per scale, angled or lateral winged, generally wind-dispersed. Chromosomes: n=11.
Genera In Family: 30 genera, 130+ species: +- worldwide, especially North America, Eurasia. Note: Incl (paraphyletic) Taxodiaceae. Taxa of (polyphyletic) Cupressus in TJM (1993) now in Callitropsis, Chamaecyparis, Hesperocyparis.
eFlora Treatment Author: Jim A. Bartel, except as noted
Scientific Editor: Thomas J. Rosatti.
Genus: ThujaView Description 

Stem: trunk generally flared at base; branches spreading to +- pendent, tips often upturned; young shoots 4-sided, in flat clusters, held horizontally. Leaf: opposite, 2-ranked, +- not appearing whorled in 4s, closely appressed, scale-like, exposed part +- as long as wide. Pollen Cone: terminal. Seed Cone: erect to reflexed, woody, ovoid-oblong, tapered to point, maturing 1st year; scales in 4--6 pairs, +- overlapping, sharp-pointed near tip, thin, oblong, acute, leathery, middle 2--3 pairs fertile. Seed: (1)2 per fertile scale, wings 2, +- equal; cotyledons 2.
Species In Genus: 5 species: northern North America, eastern Asia. Etymology: (Greek: resinous tree)

Thuja plicata D. Don
Habit: Tree 30--70 m. Stem: bark 1--2 cm thick, cinnamon-red, fibrous; young shoot upper surface glossy dark green, lower surface generally faintly white-streaked. Pollen Cone: red-brown turning dark gray. Seed Cone: 10--19 mm, light brown. Seed: 4--6 mm, narrow, elliptic, light brown. Chromosomes: n=11.
Ecology: Coastal conifer forest; Elevation: < 1800 m. Bioregional Distribution: NCo, KR, NCoRO (Del Norte, Humboldt cos.); Distribution Outside California: to Alaska, Montana.
eFlora Treatment Author: Jim A. Bartel
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botanical illustration including Thuja plicata


Citation for this treatment: Jim A. Bartel 2016. Thuja plicata, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on May 04, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on May 04, 2016.

Geographic subdivisions for Thuja plicata:
NCo, KR, NCoRO (Del Norte, Humboldt cos.);
Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.