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Isatis tinctoria
WOAD

Higher Taxonomy
Family: Brassicaceae (Cruciferae)View DescriptionDichotomous Key

Common Name: MUSTARD FAMILY
Habit: Annual to shrub; sap pungent, watery. Leaf: generally simple, alternate; generally both basal, cauline; stipules 0. Inflorescence: generally raceme, generally not bracted. Flower: bisexual, generally radial; sepals 4, generally free; petals (0)4, forming a cross, generally white or yellow to purple; stamens generally 6 (2 or 4), 4 long, 2 short (3 pairs of unequal length); ovary 1, superior, generally 2-chambered with septum connecting 2 parietal placentas; style 1, stigma entire or 2-lobed. Fruit: capsule, generally 2-valved, "silique" (length >= 3 × width) or "silicle" (length < 3 × width), dehiscent by 2 valves or indehiscent, cylindric or flat parallel or perpendicular to septum, segmented or not. Seed: 1--many, in 1 or 2 rows per chamber, winged or wingless; embryo strongly curved.
Genera In Family: +- 330 genera, 3780 species: worldwide, especially temperate. Note: Highest diversity in Mediterranean area, mountains of southwestern Asia, adjacent central Asia, western North America; some Brassica species are oil or vegetable crops; Arabidopsis thaliana used in experimental molecular biology; many species are ornamentals, weeds. Aurinia saxatilis (L.) Desvaux in cultivation only. Aubrieta occasional waif in central NCoR, Carrichtera annua (L.) DC. in SCo, Iberis sempervirens L., Iberis umbellata L. in PR, Teesdalia coronopifolia (Bergeret) Thell., Teesdalia nudicaulis (L.) W.T. Aiton in southern NCoRO, CCo. Cardaria, Coronopus moved to Lepidium; Caulostramina to Hesperidanthus; Guillenia to Caulanthus; Heterodraba to Athysanus; California taxa of Lesquerella to Physaria; Malcolmia africana to Strigosella.
eFlora Treatment Author: Ihsan A. Al-Shehbaz, except as noted
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: IsatisView Description 

Habit: [Annual] biennial [perennial herb]; hairs simple or 0. Leaf: rosetted or not, petioled, entire or lobed; cauline sessile, base lobed to clasping. Inflorescence: elongated. Flower: sepals erect to ascending, base not sac-like; petals yellow or cream, not clawed. Fruit: indehiscent, pendent, oblong to oblanceolate or round to ovate, flat perpendicular to septum, unsegmented, winged; style 0, stigma entire. Seed: 1(2), oblong, plump.
Species In Genus: +- 60 species: Eurasia. Etymology: (Greek: plant with dark dye)

Isatis tinctoria L.
NATURALIZED
Habit: Biennial, glaucous, glabrous or hairy proximally. Stem: (3)4--10(15) dm, branched distally. Leaf: basal (3)6--20(25) cm, oblong to oblanceolate, entire to wavy or dentate; cauline entire. Inflorescence: panicle of racemes. Flower: sepals 1.5--2.8 mm; petals 2.5--4 mm, 0.9--1.5 mm wide, oblanceolate, yellow. Fruit: (0.9)1.1--2(2.7) cm, 3--6(10) mm wide, oblong-oblanceolate to elliptic-obovate; pedicel reflexed, 5--10 mm, club-shaped near tip. Seed: 2.3--3.5(4.5) mm, oblong. Chromosomes: 2n=14,28.
Ecology: Disturbed areas, pastures; Elevation: 100--2200 m. Bioregional Distribution: KR, CaR, n SNH, MP; Distribution Outside California: western and eastern North America, native to Eurasia. Flowering Time: Apr--Jul Note: Once cultivated as source of the blue dye woad.
eFlora Treatment Author: Ihsan A. Al-Shehbaz
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Citation for this treatment: Ihsan A. Al-Shehbaz 2016. Isatis tinctoria, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=29342, accessed on May 31, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 31, 2016.


Isatis tinctoria
click for enlargement
© 2009 Neal Kramer
Isatis tinctoria
click for enlargement
© 2014 Julie Kierstead Nelson
Isatis tinctoria
click for enlargement
© 2009 Neal Kramer
Isatis tinctoria
click for enlargement
© 2014 Julie Kierstead Nelson

More photos of Isatis tinctoria in CalPhotos


Geographic subdivisions for Isatis tinctoria:
KR, CaR, n SNH, MP;
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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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 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.