Australian Tropical Rainforest Plants - Online edition

Cosmos caudatus Kunth

Herb (herbaceous or woody, under 1 m tall)
Shrub (woody or herbaceous, 1-6 m tall)
Click/tap on images to enlarge
Flower head. © A. Ford & F. Goulter
Scale bar 10mm. © CSIRO
Cotyledon stage, epigeal germination. © CSIRO
10th leaf stage. © CSIRO

Kunth, K.S. (1820) Nova Genera et Species Plantarum 4 : 240. Type: Crescit prope Havanam Insulae Cubae .. Floret Martio.

Common name



Usually flowers and fruits as a shrub about 1-1.5 m tall but occasionally flowers when smaller.


Leaves and leaflets variously lobed and divided. Leaflets sessile or very shortly stalked. Leaf and leaflet blades very variable in size.


Flowering heads about 45 mm diam. Individual disk flowers small, about 3.5-4 mm diam. Anthers lanceolate, about 2-4 mm long, fused to one another to form a tube around the style. Filaments free from one another, about 3 mm long, clothed in translucent fleshy hairs. Style about 10-19 mm long with two papillose stigmatic branches at the apex.


Fruit about 16-21 mm long, clothed in hooked hairs which cause them to adhere to clothes. Seeds about 6-9 mm long. Cotyledons about 3 mm long, about as wide as the radicle.


Cotyledons about 34-38 x 5-5.5 mm, sessile or shortly stalked. First pair of leaves lobed with about five segments, petioles about 4-6 mm long, winged and grooved on the upper surface. At the tenth leaf stage: leaves pinnate and the leaflets so deeply divided as to be almost bipinnate. Stem longitudinally ribbed. Seed germination time 12 days.

Distribution and Ecology

An introduced species originally from tropical America, now naturalised in CYP, NEQ and southwards to coastal central Queensland. Altitudinal range from near sea level to 800 m. Usually grows around old settlements or as a weed of agricultural land. Also found in open forest and sometimes in vine thickets and monsoon forest.

RFK Code
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