Mentzelia sp. Family: Loasaceae – Loasa Family Mentzelia is the only genus of this family represented at Arches National Park. Many species in this genus are difficult to place with certainty because of the variability of plant size, leaf size, flower size and capsule size and shape. Mentzelia albicaulis (Whitestem blazing star): Annual herbs; 3.9” to 1.3' (1 to 4 dm) tall; white or greenish-white stems Mentzelia multiflora (Desert blazing star; Desert stickleaf): Perennial herbs from a taproot; 16” to 2.6' (4 to 8 dm) tall Mentzelia pterosperma (Wingseed stickleaf): Perennial, biennial herbs, or flowering the first year; 2” to 1' (0.5 to 3 dm) tall; stems white with stiff coarse hairs Mentzelia pumila ( Wyoming stickleaf): Biennial or short-lived perennial herbs from a stout taproot; whitish stems; 7.9” to 1.97' (2 to 6 dm) tall Leaves: Mentzelia albicaulis: alternate; simple; lower leaves 1.2” to 5.9” (3 to 15 cm) long, entire, lobed or pinnatifid; upper leaves lance-shaped or linear, lobed or pinnatifid Mentzelia multiflora: alternate; simple, can be lobed or toothed or pinnatifid; rough vegetation with rough, hooked, or even stinging hairs, hairy leaves; leaves are sticky, sand often sticks to their surfaces; lower leaves 1” to 4.8” (2.5 to 12 cm) long Mentzelia pterosperma: alternate; simple; basal rosette leaves 1.2” to 2.9” (3 to 7.4 cm) long, 0.4” to 0.8” (10 to 20 mm) wide; leaves also along stems; hairy Mentzelia pumila: alternate; simple; 3.3” to 7.9” (8.5 to 20 cm) long Flowers: Mentzelia albicaulis: inflorescence with 1 to 3 flowers; 5 petals, 0.08” to 0.35” (2 to 9 mm) long; numerous stamens Mentzelia multiflora: inflorescence with 1 to 3 flowers; 10 distinct yellow petals (the inner 5 somewhat shorter and narrower), petals 0.35” to 0.8” (9 to 20 mm) long, 0.24” to 0.32” (6 to 8 mm) wide, (described as 5 proper petals with 5 alternating petaloid staminodes in Intermountain Flora, Vascular Plants of the Intermountain West, U.S.A.); 4 to 5 sepals; numerous stamens which can be petaloid (can be as many as 200 stamens); 1 style Mentzelia pterosperma: 10 yellow petals, 0.35” to 0.8” (9 to 20 mm) long, 0.16” to 0.3” (4 to 8 mm) wide, (described as 5 proper petals with 5 alternating petaloid staminodes in Intermountain Flora, Vascular Plants of the Intermountain West, U.S.A.); numerous stamens; outer stamens petaloid, 0.2” to 0.3” (5 to 8 mm) wide Mentzelia pumila: inflorescence with 1 to 3 flowers; 10 yellow yellow or golden petals, often with a darker, orange to red-brown area at the base, 0.35” to 0.6” (9 to 15 mm) long, (described as 5 proper petals with 5 alternating petaloid staminodes in Intermountain Flora, Vascular Plants of the Intermountain West, U.S.A.); numerous stamens; outer stamens are petaloid, 0.6” to 0.8” (15 to 20 mm) long Pollinators: some Mentzelia species are pollinated by bees Fruits: capsule Blooms in Arches National Park: April, May, June, July, August, September, October Habitat in Arches National Park: desert shrub communities Location seen: park road mile 0 to 2.5, park road mile 8, around Visitor Center buildings Other: The genus name, “Mentzelia”, honors Christian Mentzel (1622-1701), a German botanist. The species name, “albicaulis”, means “white-stemmed”; the species name, “multiflora”, means “many flowers” referring to the quantity of flowers; the species name, “pterosperma”, means “having winged seeds”; and the species name, “pumila”, means “dwarf”. |
Last updated: January 7, 2023