Australian Tropical Rainforest Plants - Online edition

Tridax procumbens L.


Weed
Herb (herbaceous or woody, under 1 m tall)
Click/tap on images to enlarge
Flower [not vouchered]. CC-BY J.L. Dowe
Herbarium specimen. © DERM
Family

Linnaeus, C. (1753) Species Plantarum Edn. 1 2: 900. Type: Habitat in vera Cruce.

Common name

Tridax Daisy

Stem

Stems decumbent, producing roots at the nodes, up to 50 cm tall. Stems clothed in pale hairs.

Leaves

Leaf blades 30-60 x 15-35 mm, clothed in hairs, lateral veins 2-3 on each side of the midrib.Petioles hairy, 5-10 mm long.

Flowers

Flowers produced in heads about 10 x 10-12 mm. Peduncles hairy,11-20 cm long. Heads surrounded by bracts, the outer bracts hairy, each bract about 7 x 4 mm, inner bracts glabrous, 7-8 mm long. Calyx (pappus) consists of barbed or fimbriate hairs 10-12 mm long. Corolla on the ray florets ligular, 9-10 x 4 mm, apex 3-lobed. Corolla of the disk florets tubular, about 5 mm long, corolla lobes about 0.5 mm long. Stamens fused to form a tube. Ovary 2-2.2 x 1 mm, densely clothed in long pale brown or golden hairs.

Fruit

Achene 1.6-2 mm long; pappus of slender, plumose bristles 5-6 mm long, with fine spreading hairs.

Seedlings

Features not available.

Distribution and Ecology

An introduced species that occurs in WA, NT, CYP, NEQ, CEQ and north-eastern New South Wales. Altitudinal range from near sea level to 915 m.  Found in edges of rainforest also in Eucalypt woodland, grassland and in dune vegetation.

Natural History & Notes

This weedy species has now become widespread throughout the tropics and subtropics.

Contact with this plant can sometimes cause skin irritation (Du Puy et al. 1993)

RFK Code
4030
Copyright © CSIRO 2020, all rights reserved.