Asteraceae Hymenoxys acaulis

Three images of yellow flowers on tall stems with thin pointed leaves close to the ground.

Hymenoxys acaulis

Synonym: Tetraneuris ivesiana

Family: Asteraceae (A Utah Flora – Compositae) – Sunflower Family

Perennial aromatic herbs from a taproot; up to 20” (50 cm) tall

Leaves: all basal or some upper ones along stem alternate; simple; entire; has hairs (woolly at the base giving this plant it's common name); 0.16” to 2.4” (0.4 to 6 cm) long, 0.04” to 0.32” (1 to 8 mm) wide

Flowers: ray flowers and disk flowers; flower head appears to be a single flower, but is composed of several flowers (a composite). 5 to 15 yellow fertile rays 0.12” to 0.8” (3 mm to 2 cm) long; yellow disk flowers perfect, fertile, 0.24” to 0.8” (6 to 20 mm) wide

Pollinators: other genera in this family are pollinated by insects

Fruits: achene – 1 seeded with hard shell

Blooms in Arches National Park: March, April, May, June, July, August

Habitat in Arches National Park: desert shrub, grassland and pinyon-juniper communities

Location seen: park road mile 0 to 2.5, hill behind visitor center, park road near Salt Valley overlook

Other: The genus name, “Hymenoxys”, is from the Greek “hyme” which means “membrane” and “oyxs” which means “sharp” in reference to the pointed pappus scales. The species name, “acaulis”, means “without a stem” and refers to the very short woody base of the plant.

This family is the most advanced and complex of the dicots. The family is rich in oils and resins and is found in every part of the world, but is infrequent in the tropical rainforest. Aquatic or semi-aquatic species are also uncommon.

Last updated: December 12, 2022

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