Volume 13 > Part 2 > Year 2016 > Page 267 > Compositae (Asteraceae) > Cyanthillium

1. Cyanthillium cinereum (L.) H.Rob.wfo-0000051035

Proc. Biol. Soc. Washington 103(1): 252. 1990; Bunwong, Chantar. & S.C.Keeley, PhytoKeys 37: 63. 2014.— Conyza cinerea L., Sp. Pl. : 862. 1753.— Vernonia cinerea (L.) Less., Linnaea 4: 291. 1829.

Accepted Name : This is currently accepted.

Description : Annual herb, 20–100 cm tall; stem erect, conspicuously ribbed, sericeous. Leaves 3–5 by 2–3 cm, lanceolate or ovate to broadly ovate, apex acute to acuminate, base attenuate, margins undulate to serrate, chartaceous, upper surface sericeous without glands, lower surface sericeous with cylindrical hairs, T-shaped hairs and capitate glands, lateral veins 5–7 pairs, petioles to 2 cm long. Inflorescences terminal or axillary, paniculate. Capitula campanulate, 5–6 mm long, pedunculate; involucres campanulate, 4–4.5 by 2.5–3 mm; phyllaries 3- or 4-seriate, imbricate, green with purple apex, margins piliferous, outer surface sericeous glandular, outer and middle lanceolate, apex acute to acuminate, inner lanceolate to oblong, apex acuminate; receptacle flat, 2–2.5 mm diam., alveolate, glabrous. Florets 25–30; corollas funnelform, purple or white, puberulous glandular, basal tubes 3–3.5 mm long, 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 setuliferous with twin hairs and capitate glands; pappus bristles biseriate, inner 3–3.5 mm long, persistent.

Thailand : NORTHERN: Mae Hong Son, Chiang Mai, Chiang Rai, Phitsanulok, Nakhon Sawan; NORTH-EASTERN: Phetchabun, Loei, Nong Bua Lam Phu, Udon Thani, Nong Khai, Sakon Nakhon, Nakhon Phanom, Mukdahan, Kalasin, Maha Sarakham, Khon Kaen; EASTERN: Chaiyaphum, Nakhon Ratchama, Ubon Ratchathani; SOUTH-WESTERN: Kanchanaburi; CENTRAL: Lop Buri, Saraburi, Nakhon Nayok, Krung Thep Maha Nakhon (Bangkok); PENINSULAR: Chumphon, Ranong, Phangnga, Phuket.

Distribution : Tropics and subtropics.

Ecology : Open areas of dipterocarp or dry evergreen forests, 0–250 m alt. Flowering: January–December.

Vernacular : Mo noi (หมอน้อย), ya dok kao (หญ้าดอกขาว), ya la ong (หญ้าละออง)(Bangkok); kan thup (ก้านธูป)(Chanthaburi), thua hae din (ถั่วแฮะดิน), farang khok (ฝรั่งโคก)(Loei); suea sam kha (เสือสามขา)(Trat).

Notes: This species is a widespread weed of disturbed areas throughout the tropics. It is widely known by its former name, Vernonia cinerea. Its leaf shape and capitula size vary continuously so that plants in dry areas frequently have small capitula and leaves while those in more mesic situations have larger capitula and leaves.