Common name: Mexican Sunflower
Tithonia rotundifolia (Mill.) S.F.Blake APNI*
Description: Annual herb to 2 m high; stem erect, terete, striate, pubescent at first then glabrescent.
Leaves ovate to triangular, 7–27 cm long, 4–20 cm wide, apex acuminate, base tapered and decurrent, margins rounded-toothed, sometimes 3–5-lobed, scabrous; petiole 3–5 cm long.
Peduncles up to 30 cm long; heads 3–4 cm diam.; receptacle scales prominent in fruiting head, c. 1.5 cm long, rigid, with acute tips; involucral bracts ± equal, linear to lanceolate, 2- or 3-seriate, subtending the ray florets. Ligules 9–13, yellow or orange, ovate, 3-toothed, c. 25 mm long. Disc florets numerous, c. 10 mm long, outer surface pilose, orange.
Achenes ± compressed, obtusely 4-angled, appressed-pilose, 6–8 mm long; awns 2, slender, unequal, not persistent, 3–5 mm long.
Distribution and occurrence: Recorded only from Merriwa district. Native of C Amer.
NSW subdivisions: *CWS
Other Australian states: *Qld
Text by L. Murray
Taxon concept: Flora of NSW 3 (1992)
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
***The AVH map option provides a detailed interactive Australia wide distribution map drawn from collections held by all major Australian herbaria participating in the Australian Virtual Herbarium project.