"Agoseris", a genus name given by Rafinesque in 1819, is Greek for "goat chicory".

Foothills, montane, subalpine. Meadows. Summer.
Above: Lizard Head Meadow, July 15, 2020; Calico Trail, August 25, 2014; and East Fork Trail, August 28, 2015.
Left and below: Navajo Lake Trail, July 6, 2004 and August 6, 2014; La Sal Mountains, Utah, July 31, 2010; Abajo Mountains, Utah, September 6, 2013.

The leaf shape is different, the flower color is different, but the resemblance to the common yellow Dandelion is unmistakable.  Agoseris aurantiaca is far less abundant than Dandelions, occurring in few scattered rather than in many large colonies. Look for it tucked into grasses and other wildflowers, commonly right at the side of the trail. The color and shape are unmatched by any other wildflowers, so this is an easy plant to identify.

Agoseris aurantiaca has two varieties:

Agoseris aurantiaca variety purpurea has conspicuously imbricate phyllaries that are abruptly narrowed or rounded at the tip. Several floras indicate that the phyllaries of this variety are usually glabrous and that the achenes ("the seeds") are gradually tapered at the apex.

Agoseris aurantiaca variety aurantiaca has phyllaries about equal in length and the phyllaries are usually gradually tapered to the tip. Several floras indicate that the phyllaries of this variety are usually covered in long, soft hairs ("villous") and that the achenes are abruptly tapered at the apex.

Ackerfield's Flora of Colorado adds the width of the phyllaries as a factor that separates the two varieties: phyllaries from 3-6 mm wide belong to variety purpurea; phyllaries usually less than 3 mm wide belong to variety aurantiaca. No other floras even mention the phyllary width.

Only the two pink A. aurantiaca photographs below are variety purpurea. The others all have gradually tapering, hairy phyllaries of the same length and are thus variety aurantiaca.

Agoseris aurantiaca was first collected for science by Thomas Drummond in the Canadian Rockies in the 1820s; it was named Troximon aurantiacum by William Hooker in his Flora Boreali-Americana in 1833. (Click the title to read.)  It was renamed Agoseris aurantiaca by Edward Greene in 1891 and has endured quite a few other name changes since then.

"Aurantiaca" is Latin for "orange" but the flower color can vary from orange

to the typical rusty orange to lavender to the rare pink.

Foothills, montane, subalpine, alpine.  Meadows.   Summer.
Above: Colorado Trail above Hillside Drive, August 25, 2022.
Left: Colorado Trail above Roaring Fork, August 7, 2004.

Agoseris glauca is considerably more common than and very similar to Agoseris aurantiaca, but it is a slightly larger plant in leaf, flower, and overall plant size. The quite visible difference is flower color.  Leaves in both species are very similar: long, strap-like, vertical, and frequently red/purple or with a red/purple mid-vein. Cronquist indicates that A. glauca and A. aurantiaca might hybridize.

Agoseris glauca can be so abundant that it forms a significant diet for small critters. The above photograph, taken at about 11,500 feet, shows a cache of seeds harvested from Agoseris glauca and ready to be pulled into the burrow.

The plant was first collected by Thomas Nuttall on the banks of the Missouri River in about 1811 and was named Troximon glaucum by Frederick Pursh in 1814 in his Flora Americae Septentrionalis.  It was renamed Agoseris glauca by Constantine Rafinesque in 1833.  "Glauca" is Greek for "gray", but in the botanical sense it means that the plant has a blue/green or white, often waxy, bloom or powdery coating on the stem or leaves. This glaucous coating usually can be rubbed off with a wipe of the finger.

Agoseris glauca (Mountain Dandelion)
Asteraceae (Sunflower Family)

Foothills, montane, subalpine, alpine.  Meadows.   Summer.
Lizard Head Trail, August 31, 2004;
Cross Mountain Trail, August 7, 2004;
Middle Calico Trail, August 9, 2004;
Eagle Peak Trail, August 29, 2014.