Eriogonum umbellatum var. cladophorum


Bull. Soc. Roy. Bot. Belgique 42: 198. 1906.

Common names: Yellowstone sulphur flower
Synonyms: Eriogonum rydbergii Greene
Treatment appears in FNA Volume 5. Treatment on page 339.

Herbs, compact mats, 1–2 × 2–5 dm. Aerial flowering stems erect, 1–2 dm, tomentose to densely floccose, without one or more leaflike bracts ca. midlength. Leaves in tight rosettes; blade usually elliptic to ovate, 1–2 × 0.5–1.5 cm, lanate to densely tomentose on both surfaces, margins plane. Inflorescences umbellate; branches 0.3–2.5 cm, without a whorl of bracts about midlength; involucral tubes 2–3 mm, lobes 1.5–3 mm. Flowers 4–7 mm; perianth bright yellow.

Phenology: Flowering Jun–Sep.
Habitat: Sandy to gravelly flats, sagebrush communities, montane conifer woodlands
Elevation: 2000-2300 m


Variety cladophorum is a rare and localized expression known from three locations (Upper Geyser Basin, Old Faithful, and Madison Junction) within Yellowstone National Park, Teton County.

Selected References


Lower Taxa