Institute for Biodiversity Science and Sustainability
Distribution Map

The colors below indicate the kind of documentation available for this species in the California counties where it occurs.


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Hayfield Tarweed
Hemizonia congesta ssp. congesta

Here is the classic botanical description: "Leaves silvery canescent, inflorescence campanulate, phyllary tips shorter than body, ray flower ligules yellow". When the foliage is gently brushed, these annuals give off a distinctive tar-like odor. The yellow flowers appear in early to late summer, often long after the last rains. There is a presumed relationship between the resin and the plant's drought resistance. The specifics of this relationship are unknown and could be an avenue of research for the enterprising graduate student.

DISTRIBUTION: Coastal grasslands (sometimes on serpentine) from the southern North Coast Ranges to the San Francisco Bay Area; < 300 m.
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