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Cosmos caudatus

Family

Asteraceae

Botanical Name

Cosmos caudatus Kunth

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

Common name

Cosmos

Weed

*

Stem

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

Leaves

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

Flowers

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

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.

Seedlings

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.

Distribution and Ecology

An introduced species originally from tropical America, now naturalized 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.

CYP

X

NEQ

X

Herb (herbaceous or woody, under 1 m tall)

X

Shrub (woody or herbaceous, 1-6 m tall)

X

RFK Code

3334