Volume 13 > Part 2 > Year 2016 > Page 178 > Compositae (Asteraceae) > Ageratina

Ageratina adenophora (Spreng.) R.M.King & H.Rob.wfo-0000022875

Phytologia 19(4): 211. 1970; Grierson & D.G.Long, Fl. Bhutan 2(3): 1624. 2001; H.Koyama, Bull. Natl. Sci. Mus., Tokyo, B 28(2): 59. 2002; Y.L.Chen et al., Fl. China 20–21: 880. 2011.— Eupatorium adenophorum Spreng., Syst. Veg. ed. 16, 3: 420. 1826; Backer & Bakh.f., Fl. Java 1: 378. 1965; Kitam. & Gould in Hara, Chater & Williams (eds), Enum. Fl. Pl. Nepal 3: 27. 1982. Plate XVII: 9.

Accepted Name : This is currently accepted.

Description : Herb to shrub; stems erect, often woody at base, dark purple, branches (including inflorescences), petioles and phyllaries with glandular hairs, upper part branched, branches ending in inflorescences. Leaves ovate or ovate-rhomboid, 4–10 by 3.5–6.5 cm, apex acuminate, rather acute, base shortly tapering, margins serrate, both surfaces glabrate except on veins, younger leaves pubescent; petioles 1.5–3.5 cm long. Inflorescences densely corymbose; peduncles 2–10 mm long. Capitula subglobose; involucres, ca 5 by 8–10 mm; phyllaries 3-seriate, imbricate, outer linear-lanceolate, apex acute, abaxial surfaces stipitate-glandular, inner lanceolate, ca 4 mm long, somewhat scarious; receptacle slightly convex, glabrous. Florets 75–80 per capitulum, bisexual; corollas funnel-shaped, ca 3 mm long. Achenes oblong, ca 1.5 by 0.3 mm, 5-angled, acutely angled, black, glabrous; pappus of ca 10 capillary bristles, ca 3 mm long, dirty white.

Thailand : NORTHERN: Chiang Mai (Doi Inthanon, Pha Sam Thao, Pha Hom Pok).

Distribution : Weedy and widely adventive in many tropical and subtropical parts of the World (America – type).

Ecology : Old clearings in mountain areas, 1,300–2,500 m alt. Flowering: October–January.

Vernacular : Sap ma (สาบหมา)(Chiang Mai), crofton weed.