DICOTYLEDONS

AMARANTHACEAE - Amaranth Family

A family of over 900 annual and perennial species, predominantly herbs and shrubs but with a few climbers, found throughout tropical, sub-tropical and temperate regions. There are about 110 native species in Western Australia and up to 15 naturalised species. Aerva javanica (kapok bush) was introduced to assist with the revegetation of degraded rangelands. It is now widespread in many types of vegetation from Carnarvon to the Kimberley, although it prefers calcareous soils. It is a perennial herb, up to 1.6m, densely covered in short, branched hairs, giving it a greyish appearance. Flowers and fruits for most of the year. Native of northern Africa to south west Asia. It is unrelated to the true kapok tree, which is exploited commercially.


Aerva javanica, GK

Alternanthera philoxeroides (alligator weed) DP is a perennial aquatic plant that can also grow on swampy land. It has hollow creeping stems that can reach 10m in length. The leaves grow in opposite pairs and are hairless with conspicuous veins radiating from a central nerve. It produces white, papery flowers about 1cm in diameter in summer. (The Western Australian native A. nodiflora (joyweed) is similar in appearance but much less robust.) Alligator weed is a potentially troublesome water weed that has been cultivated in Perth and is a target for eradication in Western Australia. It is native to tropical and sub-tropical South America.


Alternanthera philoxeroides, RR

A. pungens (khaki weed) is a native of America. It is a prostrate perennial with a large, carrot-like root system, found in seasonally moist habitats in verges, wasteland and disturbed river margins. Its stems may reach 50cm in length and root at the nodes. The flowers emit a pungent odour and the fruits are extremely spiny. There are seven native species of Alternanthera (joyweeds) with which it can be confused. Other than the smell, A. pungens can be recognised by having broadly elliptical rather than oblong or narrow leaves, and sepals that are unequal in length. Native to South America.


Alternanthera pungens, RR

There are approximately eight native and nine introduced species of Amaranthusin Western Australia. The weeds are annual herbs, some growing to 1m. A. caudatus (love lies bleeding) is perhaps the most distinctive, with its deep red, drooping flower tassels. It is a garden escape, naturalised in a few places in the south-west of the State; originally from South America.


Amaranthus caudatus, RR

A. viridis (green amaranth) has been found near Broome and around settlements in the south-west. It has upright, green flower spikes in summer in the south-west and April - June in the north. Native to tropical America.


Amaranthus viridis, RR

A. albus (tumbleweed) is found on road verges and wasteland in the south-west. It can be distinguished by its rigid, white stems and in summer by the clusters of flowers in the axils of the leaves (flower spikes in most other species are terminal). It is native to North America. Several other species have been recorded around settlements and in disturbed areas, including: A. cruentus, south-west (native to North America and Asia); A. hybridum, Kimberley (a worldwide weed); A. lividus, south-west (native to Europe);


Amaranthus albus, RR

A. powellii (Powell's amaranth) south-west (native to North America); A. retroflexus, south-west (native to North America); A. tricolor (Joseph's coat) Kimberley and Dampier Archipelago (widespread in tropical regions). Most are difficult to distinguish and a specialist text should be referred to for details.


Amaranthus powellii, RC

Gomphrena celosioides (gomphrena weed) is a sprawling herb, with greenish flowering spikes in summer. Originally from South America, it is spreading rapidly in irrigated areas of most major settlements in the Kimberley, and is also recorded from Exmouth. There are numerous native species in this genus: if the plant is not growing in a lawn, a specialist botanical text should be consulted for confirmation of identity. Guilleminea densa (small matweed) is a prostrate, mat-forming perennial with lateral clumps of yellow-green flower heads. Native to south-west USA, Mexico and north-west South America, it has become established in the Kimberley and is spreading rapidly in mown lawns, camping areas and along roadsides.


Gomphrena celosioides, PH

Ptilotus polystachyus (bottlewashers, green mullamulla) is the most widespread of all the mullamullas, native from Perth to the Kimberley. It has numerous forms, ranging from post-fire annuals in the desert, to resprouting perennials around Perth. In the south-west it is normally perennial, forming an open soft shrub to 70cm tall by 1m wide, bearing long, linear-elliptical leaves and erect, cylindrical spikes of green, honey-scented flowers. This species is a disturbance opportunist, flourishing after fires, grazing or road grading and is increasing in such sites in the wheatbelt. It should not be used for rehabilitation outside its natural range. Pupalia lappacea is a prostrate, scrambling or erect herb from Africa to south-east Asia, that has become a weed of rainforest patches in the Kimberley. It is densely hairy, with ovate leaves. The fruit is a spiny burr. Flowers and fruits from March to July.


Ptilotus polystachyus, PH

 

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