Ovateleaf Cacalia

Arnoglossum ovatum is the most variable species in the genus (as implied by synonymy). Extreme forms (very narrow-leaved, e.g., Cacalia lanceolata form, and broadly ovate-leaved forms) look very distinctive; intergradations occur. Differences could be because of dysploid chromosome races, variances in habitat, or some unknown factors.

Plants 50–300 cm (weakly rhizomatous). Stems round. Basal leaves: blades ovate to narrowly lanceolate or lance-linear, to 30+ cm, margins usually entire. Cauline leaves: proximal petiolate, ovate to narrowly lanceolate or lance-linear, margins usually entire; distal sessile, smaller. Involucres 8–10 mm. Phyllaries (± purple-tinged) lance-ovate, midveins not winged (tips acute to acuminate, papillate). Corollas usually white or greenish, rarely purplish, 8–9(–10) mm. Cypselae fusiform or clavate, 4–5 mm (dark brown, 7–8-ribbed); pappi (5–)6–7.5 mm. 2n = 50, 52, 56.

Cacalia ovata Walter, Fl. Carol., 196. 1788; Arnoglossum ovatum var. lanceolatum (Nuttall) D. B. Ward; C. elliottii (R. M. Harper) Shinners; C. lanceolata Nuttall; C. lanceolata var. elliottii (R. M. Harper) Kral & R. K. Godfrey; Conophora ovata (Walter) Nieuwland; Mesadenia angustifolia Rydberg; M. dentata Rafinesque; M. elliottii R. M. Harper; M. lanceolata (Nuttall) Rafinesque; M. lanceolata var. virescens R. M. Harper; M. maxima R. M. Harper; M. ovata (Walter) Rafinesque; Senecio boscianus Schultz-Bipontinus; S. walteri Schultz-Bipontinus

Arnoglossum ovatum, the ovateleaf cacalia, is a species of plant in the sunflower family. It is native to the southeastern and south-central United States from southern North Carolina to Florida and eastern Texas.

Arnoglossum ovatum is a large plant growing up to 300 cm (120 inches or 10 feet) tall. Flower heads are small but numerous, usually white or pale green, occasionally slightly purplish. The species grows in sandy woods, savannahs, and roadsides.