Crassocephalum crepidioides (Benth.) S Moore
Africa and Madagascar
This is an erect or straggling annual herb (living 1 season only).
Leaves are alternately arranged along the stem. Leaf shape is variable, smaller upper leaves are generally elliptical, larger lower leaves have two lobes at the base. All leaves have toothed margins.
Flower heads droop while forming and are orange-pink.
Base of plant, lower stems, some veins and some leaves have a purple colouration.
Seed has hairs (pappus) which are white and tinged reddish or mauve.
Stem is round in cross-section and exudes watery liquid when cut.
This plant is easily removed by pulling. Be careful to keep pulled plants up off the ground as stems in contact with the ground will produce roots. The seed of this plant is usually dipsersed by wind or water and can be found some metres from where the parent plant was in the previous season.
Other plants easily confused with this plant
May be confused with another weed which is Erechtites valerianifolia (Brazilian fireweed). Thickhead has relatively few buds and flowers in comparison. Erechtites has a prominently ribbed stem and its flowers are mauve.
Sources & References
"Weeds - an illustrated botanical guide to weeds of Australia" by B. A. Auld and R. W. Medd
"Suburban and Environmental Weeds - an identification and information system - South-east Queensland (and northern New South Wales)"
"Plantnet FloraOnline" (2005) http://plantnet.rbgsyd.nsw.gov.au/
Prepared by Justin KY Chu, July 2005
Checked by IEWF, March 2006