E-Flora BC: Electronic Atlas of the Flora of British Columbia

Madia gracilis (Sm.) D.D. Keck
slender tarweed (grassy tarweed)
Asteraceae (Aster family)

Introduction to Vascular Plants

© Hans Roemer  Email the photographer   (Photo ID #26145)

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Distribution of Madia gracilis
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Species Information

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Aromatic annual herb from a tap root; stems erect, simple, usually branched, roughly hairy becoming glandular upwards, 10-100 cm tall.
Basal leaves lacking; stem leaves alternate, linear to lance-linear, 2-11 cm long, 1-10 mm wide, stiff-hairy and often densely glandular upwards.
Heads with ray and disk flowers, numerous in an elongate inflorescence; involucres urn-shaped, 6-11 mm tall; involucral bracts linear dorsally, crescent-shaped laterally, glandular; ray flowers yellow, 3-9, 1.5-2 mm long; disk flowers 13-15, fertile, with black anthers.
Achenes flattened, hairless, often mottled, 2.8-5 mm long; pappus lacking.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Dry roadsides, open slopes and forest openings in the lowland, steppe and montane zones; infrequent in extreme S BC; S to UT, NV, CA and MX, disjunct in Chile.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Madia gracilis

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 120 537 925
Slope Gradient (%) 10 40 100
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
60 174 240
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 1 4
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: CDF(3), ICH(2), PP(2)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Madia dissitiflora (Nutt.) Torr. & A. Gray
Madia gracilis subsp. collina D.D. Keck
Madia gracilis subsp. pilosa D.D. Keck

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References