Little Ironweed

Leaf blades 20–35(–50+) × 12–25(–30+) mm (including petioles). Peduncles 3–10(–20+) mm. Bracts ± linear at proximal nodes, wanting distally. Phyllaries 3–4 mm. Cypselae 1.5–2 mm; pappi white, outer scales 0.1–0.3 mm, inner bristles 3–4 mm. 2n = 36.

Conyza cinerea Linnaeus, Sp. Pl. 2: 862. 1753; Vernonia cinerea (Linnaeus) Lessing

Vernonia cinerea (L) Less. Linnaea 4: 291. 1829
Conyza cinerea L. Sp. PI. 862. 1753.
Cacalia cinerea Kuntze, Rev. Gen. 323. 1891.
Seneciodes cinereum Kuntze; Post & Kuntze, Lex. Gen. Phan. 515. 1904.
Stems herbaceous, erect, simple or freely branched, 1-8 dm. high, glabrate below, cinereous-pubescent above; leaf-blades thin, bright-green, spreading, variable in shape from narrowly elliptic or oblanceolate to broadly ovate or triangular, 2-5 cm. long, acute or obtuse, serrate, crenate, or entire, abruptly constricted at the base into a margined petiole, cinereous-pubescent beneath; inflorescence corymbose, 2-10 cm. wide; braeteal leaves subulate; heads about 13flowered; involucre campanulate, 3-4 mm. high; scales loosely and irregularly imbricate, thinly pubescent, the outer subulate, the inner linear-oblong, acuminate, purplish at the apex; achenes pubescent; pappus white, the inner series 5 mm. long, the outer minute.
Type locality: India.
Distribution: Tropics of the Old World; introduced throughout tropical America as far north as Mexico and southern Florida.

Annual herbs, 20–100 cm tall. Stems erect, conspicuously ribbed, sericeous. Leaves 3–5 by 2–3 cm, lanceolate or ovate to broadly ovate, margin undulate to serrate, apex acute to acuminate, base attenuate, chartaceous; upper surface sericeous without glands; lower surface sericeous with cylindrical hairs, T-shaped hairs and capitate glands, lateral veins 5–7-paired; petioles up to 2 cm long. Capitulescences terminal or axillary, paniculate. Capitula campanulate, 5–6 mm long, pedunculate. Receptacle flat, 2–2.5 mm in diam., glabrous. Involucres campanulate, in 3–4 series, 4–4.5 mm long, 2.5–3 mm in diam. Phyllaries imbricate, green with purple apex, margin piliferous, outer surface sericeous glandular; the outer and the middle ones lanceolate, apex acute to acuminate; the inner ones lanceolate to oblong, apex acuminate. Florets 25–30; corollas funnelform, purple or white, puberulous glandular; corolla tubes 3–3.5 mm long; corolla lobes ca. 1 mm long. Anthers ca. 0.6 mm long, apical appendage acute, base obtuse. Styles purple, ca. 3 mm long, branches ca. 0.5 mm long.Achenes clavate, 1.5–1.8 mm long, ribs inconspicuous, densely pubescent with twin hairs and capitate glands. Pappus in 2 series of bristles, the inner ones 3–3.5 mm long, persistent.

Thailand: Mae Hong Son, Chiang Mai, Chiang Rai, Phitsanulok, Nakhon Sawan, Phetchabun, Loei, Nong Bua Lum Phu, Udon Thani, Nong Khai, Sakon Nakhon, Nakhon Phanom, Mukdahan, Kalasin, Maha Sarakham, Khon Kaen, Chaiyaphum, Nakhon Ratchama, Ubon Ratchathani, Kanchanaburi, Lop Buri, Saraburi, Nakhon Nayok, Bangkok, Chumphon, Ranong, Phangnga, Phuket. Tropics and subtropics.

Cyanthillium cinereum - flower head

Cyanthillium cinereum (also known as little ironweed and poovamkurunnal or poovamkurunnila in Malayalam, and monara kudumbiya in Sinhalese) is a species of perennial plants in the sunflower family. The species is native to tropical Africa and to tropical Asia (India, Sri Lanka, Indochina, Indonesia, etc.) and has become naturalized in Australia, Mesoamerica, tropical South America, the West Indies, and the US State of Florida.

Cyanthillium cinereum is an annual herb up to 120 cm (4 feet) tall. It produces flat-topped arrays of numerous flower heads, each with pinkish or purplish disc florets but no ray florets. The species can be confused with Emilia sonchifolia, but the flower bracts of the latter are much longer and vase-shaped.

Cyanthillium cinereum has been used for smoking cessation in Thailand and other countries, and as relief for the common cold.

It used to be called Vernonia cinerea, but apparently there was a taxonomic update, sometime prior to early 2014.