Jepson eFlora: Taxon page
Vascular Plants of California
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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.
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.
Jepson eFlora Author: Jim A. Bartel
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

Previous taxon: Thuja
Next taxon: Ephedraceae

Botanical illustration including Thuja plicatabotanical illustration including Thuja plicata

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Citation for this treatment: Jim A. Bartel 2012, Thuja plicata, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on July 22, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on July 22, 2024.

No expert verified images found for Thuja plicata.

Geographic subdivisions for Thuja plicata:
NCo, KR, NCoRO (Del Norte, Humboldt cos.)
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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 occurrence).


Data provided by the participants of the  Consortium of California Herbaria.

View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month Flowering-Fruiting Monthly Counts

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).