Lasthenia sect. Amphiachaenia
Madroño 48: 205. 2002.
Annuals or perennials. Leaves entire or ± toothed. Involucres campanulate to depressed-hemispheric, hemispheric, or obconic. Phyllaries ± persistent or falling with cypselae, distinct. Receptacles narrowly conic to conic (subulate in L. leptalea), muricate or papillate, glabrous. Ray corollas bright yellow, laminae 2.5–16 mm, floral pigments turning deep red in dilute aqueous alkali. Disc corolla lobes 5; anther appendages deltate to sublanceolate or subulate (broadened distal to bases); style apices ± deltate with apical tufts of hairs and subapical fringes of shorter hairs. Cypselae to 4 mm; epappose or pappose. 2n = 16, 32, 48.
Distribution
w United States, nw Mexico.
Discussion
Species 4 (4 in the flora).
Perennial lasthenias are found only in sect. Amphiachaenia. Epappose plants of sect. Amphiachaenia are more likely to be found in coastal populations and may constitute entire local populations.
Selected References
Key
| 1 | Stems glabrous proximally, villous distally; phyllaries usually 4–6, glabrous but for apices; receptacles subulate, papillate; anther appendages subulate; interior w California | Lasthenia leptalea |
| 1 | Stems ± hairy throughout, sometimes more so distally; phyllaries 4–16, hairy; receptacles conic, muricate; anther appendages deltate to sublanceolate; Arizona, California, Oregon | > 2 |
| 2 | Perennials; coastal Oregon | Lasthenia ornduffii |
| 2 | Annuals or perennials; coastal or inland Arizona, California, Oregon | > 3 |
| 3 | Annuals; leaves entire; pappi usually of (2–)4(–6) opaque, white (aging to brown), ovate-lanceolate, aristate scales, sometimes 0; Arizona, California (includingChannel Islands) | Lasthenia gracilis |
| 3 | Annuals or perennials (if perennial, only in coastal California); leaves entire or with 3–5+ teeth; pappi 0, or of 1–7 translucent (rarely opaque), brown (rarely white), linear to subulate, aristate scales; n California, s Oregon | Lasthenia californica |