Least Tarweed, Smallhead Tarweed, Small-head Tarweed
Hemizonella minima
Synonyms: Hemizonia minima, Madia minima
Least tarweed as seen on vernally moist swales on south-facing slopes near Fivemile Butte Lookout, Mt. Hood National Forest.........May 17, 2015.
Although difficult to see from this angle, the stem leaves are generally opposite. The similar least tarweed (Madia exigua) has alternate stem leaves.
What appears to be young least tarweed blooming along the summit ridge of Lookout Mountain, northern edge of the Badger Creek Wilderness..........June 21, 2014. Note that they can begin blooming as soon as emerging from the soil. This is a time when it can be hard to distinguis this species fromthe similar Madia exigua.
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The upper stem and inflorescence of least tarweed as seen in the King Mountain Rock Garden ACEC of the Umpqua National Forest.........June 25, 2005. Note the gland-tipped hairs on the involucral bracts and stems.
Least tarweed as seen atop Grizzly Peak, Cascade-Siskiyou National Monument.......May 27, 2021.
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The basal leaves of least tarweed as seen at left in the King Mountain Rock Garden ACEC of the Umpqua National Forest.......June 25, 2005. The photo at right shows the stem leaves of least tarweed in a grassy bald along the Cedar Creek Trail #457 about 4 miles east of Fifteenmile Creek Campground, Mt Hood National Forest......June 27, 2023.
Paul Slichter