Tithonia diversifolia (Hemsl.) A.Gray
Gray, A. (1883) Proceedings of the American Academy of Arts & Sciences 19 : 5.
Japanese Sunflower; Mexican Sunflower
Flowers and fruits as a shrub about 2-4 m tall.
Flowers perfumed, produced in heads with disk florets surrounded by a ring of about 10-15 sterile orange-yellow ray florets and bracts. (The whole structure would be interpreted as a single flower by most casual observers.) Ray floret perianth about 40 x 20 mm. Peduncle hollow towards the apex and rather pithy. Anthers with a lanceolate appendage at the apex. Anthers fused to one another but the filaments free. Ovary and stigmas papillose or hairy.
Hypocotyl clothed in very short hairs just visible with a x10 lens. Stem above the cotyledons clothed in long white erect hairs. First pair of leaves with toothed margins. At the tenth leaf stage: leaves generally deeply lobed, lower surface of the leaf blade densely clothed in white matted hairs. First 5 or 6 pairs of leaves are opposite, subsequent leaves alternate. Freshly broken roots emit an odour very like that of carrots (Daucus carota). Seed germination time 7 days.
An introduced species originally from Central America, now naturalised in NEQ, CEQ and southwards as far as north-eastern New South Wales. Altitudinal range in NEQ from near sea level to 850 m. Grows as a weed of agricultural land and in waste places but also found in clearings and along roads in rain forest.
This species may repel termites.