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Thuja
ARBORVITAE

Higher Taxonomy
Family: CupressaceaeView DescriptionDichotomous Key

Common Name: CYPRESS FAMILY
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.

Thuja
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)
eFlora Treatment Author: Jim A. Bartel
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Citation for this treatment: Jim A. Bartel 2016. Thuja, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=9029, accessed on July 28, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on July 28, 2016.


Thuja occidentalis
click for enlargement
© 2016 Keir Morse
Thuja occidentalis
click for enlargement
© 2016 Keir Morse
Thuja occidentalis
click for enlargement
© 2016 Keir Morse

More photos of Thuja in CalPhotos