39. Mentzelia albescens (Gillies ex Arnott) Bentham & Hooker f. ex Grisebach, Abh. Königl. Ges. Wiss. Göttingen. 19: 150. 1874.
Wavy-leaf blazingstar Wavy-leaf blazingstar
Bartonia albescens Gillies ex Arnott, Edinburgh J. Nat. Geogr. Sci. 3: 273. 1831; B. wrightii (A. Gray) Walpers
Plants biennial, candelabra-form. Stems solitary, erect, straight; branches distal, distal longest, antrorse, straight; hairy. Leaves: blade 31–92(–157) × 10.5–27.6(–41) mm, widest intersinus distance 5.2–23.3(–29) mm; proximal lanceolate or elliptic, margins serrate to pinnate, teeth or lobes 8–22, slightly antrorse, 1.8–6 mm; distal lanceolate, base clasping, margins usually serrate to pinnate, occasionally entire, teeth or lobes (0–)10–20, slightly antrorse, 1.4–7.6 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes. Bracts: margins entire. Flowers: petals golden yellow, 5.7–9.2 × 1.3–3 mm, apex usually acute, occasionally rounded, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 4.7–8.4 × 1–2.4 mm, without anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 3.5–5.4 mm. Capsules cylindric, 13.6–23.5 × 5.1–7.8 mm, base tapering, not or slightly longitudinally ridged. Seeds: coat anticlinal cell walls straight, papillae 4–17 per cell. 2n = 22.
Flowering May–Nov. Dry grasslands, xeric habitats of arroyos, roadsides, roadcuts, washes, chat piles, slopes; 200–1600 m; Kans., Mo., Okla., Tex.; South America (Argentina, Chile).
Phylogenetic analyses (J. J. Schenk and L. Hufford 2011) recovered representative populations of Mentzelia albescens from Texas and South America in a monophyletic group. Phylogenetic placement of these populations among lineages in sect. Bartonia, as well as a lack of morphological differentiation among North American and South American populations, suggests a recent dispersal to South America. In the flora area, this species is native to central and western Texas, and introduced in Kansas, Missouri, and Oklahoma.