Cyrtocymura scorpioides

Cyrtocymura scorpioides (syn. Vernonia scorpioides), known locally as piracá or erva-de-São-Simão, is a perennial herbaceous shrub in the Asteraceae native to open fields, forest margins, and disturbed ground across much of tropical and subtropical South America, including Brazil, Paraguay, Bolivia, and Argentina. Plants grow erect or scrambling, reaching 1 to 3 metres tall, with woody-based, branched stems clothed in fine grey-white tomentum. The alternate leaves are ovate-lanceolate, 5 to 15 cm long, acuminate, with serrate margins, dark green and roughly pubescent above and densely white-tomentose beneath. The inflorescence is a large, branched, scorpioid panicle of small discoid heads, each with 4 to 12 pale lilac, mauve, or whitish tubular florets surrounded by an imbricate, narrow involucre 4 to 6 mm long; the curved arrangement of heads along the branches gives the species its epithet. Achenes are small, ribbed, and topped with a double pappus of white, deciduous outer scales and longer inner bristles.