Duration: Perennial

Nativity: Native

Lifeform: Forb/Herb

General: Perennial herb, 20-80 cm tall; stems several from the base, white, stout, leafy, sparsely covered with minute, reflexed or spreading barbed hairs.

Leaves: Basal leaves early-withering; stem leaves alternate; blades linear to narrowly oblanceolate, up to 11 cm long and 5-35 mm wide, the margins entire or with a few short laciniate lobes; leaf hairs sparse, with pustulate bases.

Flowers: Yellow to cream-colored and showy, solitary at branch tips; each flower subtended by a linear bract, entire or with a few lobes near the tip; sepals and petals attached to the top of the ovary (epigynous); sepals 5 per flower, narrow, persistent in fruit; petals 10,oblanceolate, 11-13 mm long and 2-4 mm wide, sulfur-yellow when the flower is opening and quickly fading to creamy white when fully open.

Fruits: Capsules subcylindrical, 8-12 mm long and 5-6 mm wide; seeds lens-shaped, winged.

Ecology: Found on outcrops of gypsum in the Todilto Formation, from 5,500-6,000 ft (1676-1829 m); flowers open in the evening hours, from late June through September.

Distribution: North-central New Mexico

Notes: Look for this endemic on gypsum outcrops. It is distinct because of its flowers which are cream-colored when fully open, with many yellow stamens in the center of the flower; the leaves which are long and narrow, sometimes with a few lobes but often entire; the capsules which are not quite twice as long as wide; and the winged seeds. Mentzelia is a notoriously difficult genus with an overwhelming number of species and the keys are not easy to use. It is important to make collections with mature seed pods, because many key characters deal with the seeds and capsules, and some can't be seen with a hand lens in the field.

Etymology: Mentzelia is named for Christian Mentzel (1622-1701), a German botanist, botanical author and physician; todiltoensis refers to the Todilto Formation, the geologic formation to which this species is restricted.

Editor: AHazelton 2017