Amsinckia tessellata A.Gray
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Rough-hairy annual 1–6 dm; stem spreading-hispid, the upper part also with shorter and softer, somewhat retrorse hairs; lvs linear or generally broader, often lance-oblong or lance-ovate, to 10 × 3 cm; sep 7–14 mm at maturity, commonly only (2–)4 by lateral fusion, the broader one(s) often apically bidentate; cor 7–12 mm, the tube 20-nerved below the insertion of the stamens; stamens inserted near the middle of the cor-tube; nutlets 2.5–3.5 mm, roughened, often tessellate- tuberculate; 2n=24. Widespread in w. U.S., occasional with us as a weed in disturbed sites. Apr.–June.