Robinia pseudoacacia (black locust) is a deciduous tree to 15m with spiny stems and branches and pinnate leaves with 3 to 10 pairs of oval leaflets. In spring, hanging racemes of sweet-scented white flowers are produced. Reproduces by seed and suckers which form especially if the roots are damaged; these suckers are extremely thorny. A garden escape, it can be found on wasteland and along creeks from Perth to Albany. Native to eastern North America.

Robinia pseudoacacia , PH

Stylosanthes are herbs or sub-shrubs with trefoil leaves, imported as fodder crops for tropical regions. The pods, at maturity, break up into sections each containing one seed. Four are naturalised in Western Australia. S. guianensis (stylo) is a hairy perennial herb to 50cm with yellow flowers with red-brown markings produced in June and July. This species is the only one with a hairless pod. It is naturalised near Kununurra, Port Hedland and on Koolan Island. Native to Central and South America. S. hamata (Caribbean stylo) is a softly-hairy sprawling perennial to 30cm. The stems have hairs on one side only and the yellow flowers are produced from April to August. The pod usually breaks into two sections, the lower one hairy, the upper nearly hairless. Naturalised in the Kimberley. It is native to the islands of the West Indies and near-coastal areas of North, Central and South America.

Stylosanthes guianensis, GK

S. humilis (Townsville stylo) is similar to S. hamata, but it is covered with a mixture of both bristly and soft hairs, while the pod usually only has one fertile section, that is sparsely hairy. Widespread in wasteland, pindan, woodland and along creeks in the Kimberley. Native to Central and northern South America. S. scabra (was included in S. viscosa) is a sub-shrub to 1m tall. The stems are hairy all over and have three kinds of hairs, soft, bristly and sticky, which give a rusty appearance to the plant. The flowers are yellow and the pod usually breaks into two sections, both densely hairy. Naturalised in the Kimberley, along the Gibb River Road. Sutherlandia frutescens (bladder senna) is an erect, soft shrub to 1m with pinnate leaves and showy red flowers. Pods are large and inflated. A garden escape, naturalised on near-coastal limestone road verges and wasteland from Perth to Busselton. Native to South Africa.

S. humilis , RR

Trifolium (clover) is a large, widespread, Northern Hemisphere genus of about 300 species, of which many have been introduced as fodder plants and at least 28 have become naturalised in Western Australia. T. angustifolium (narrowleaf clover) is an erect annual up to 60cm tall, with relatively few, straight, unbranched stems. The large leaves have long, narrow leaflets. The stems are topped by long cylindrical heads of small pink flowers, each with a hairy calyx with five pointed, tooth-like lobes that enlarge and harden enclosing the pod at maturity, giving rise to a prickly grass-like seedhead. Flowers in spring and early summer. A weed in a wide variety of situations, common along roadsides and tracks in less fertile sites, not common in grazed pastures, throughout the south-west between Perth and Albany. No agricultural value. Native to the Mediterranean.

Trifolium angustifolium , PH

T. arvense (hare's foot clover) is an upright or spreading annual, densely covered with soft, fine hairs. The small, white to pink flowers are carried in a spherical or elongated head, at the tips of the stems. Long hairs on the calyx make the flower head softly hairy. Flowers in spring. A common weed of natural and cultivated land from Geraldton to Cape Arid, especially in less improved pastures on poorer soils. Has little agricultural value. Native to Europe, North Africa and Asia.

T. arvense , GK

T. campestre (hop clover) is a small, yellow-flowered annual with stems up to 30cm long. The globular or elongated heads contain 20 to 50 flowers, each surrounded by papery, yellow floral parts. Flowers in late winter and spring. Widespread weed of gardens, roadsides, wasteland, grazed woodland and cultivated land, particularly heavily grazed pastures, from Geraldton to Cape Arid. The seed is spread very efficiently through sheep dung. It is the third most important clover weed to agriculture, contributing some herbage in overgrazed situations. Native to Europe.

T. campestre, PH

T. dubium (suckling clover) is a small, yellow-flowered clover that resembles a medic (Medicago sp). It is a hairless or slightly hairy, creeping annual with slender stems up to 50cm long and small, widely-spaced leaves with leaflets narrower than most other yellow-flowered clovers. The flowers are in loose, roughly spherical heads. Flowers in spring. Petals turn dark brown as the fruit matures. Widespread in many disturbed natural and urban situations (especially lawns) throughout the south-west, from Geraldton to Esperance. Only found in pastures in higher rainfall areas and unimportant to agriculture. Native to Europe.

T. dubium , PH

T. fragiferum(strawberry clover) is a prostrate hairy perennial with long stems that root at the nodes. It produces a globular head of white to pink flowers in summer, on a stalk much longer than the leaves. Readily distinguished by the fruiting head in which the inflated calyces enclose the individual pods, the whole head resembling a strawberry. Native to the Mediterranean; naturalised on roadsides and wasteland in Perth and the lower south-west. It is an important pasture species in summer moist situations as it tolerates waterlogging and moderate salinity - probably the most salt-tolerant clover species.

T. fragiferum, PH

T. glomeratum (cluster clover, ball clover) is a creeping, hairless annual that produces stalkless, spherical heads of purple flowers in the axils of the leaves in spring. The leaflets are small, with finely toothed margins. Probably the most important species to agriculture, especially in heavily-grazed pastures on acid soils in all rainfall zones. It is also a widespread weed of swamps, granite outcrops, wasteland, roadsides and urban bushland in settled districts from Kalbarri to Cape Arid. Native to western and southern Europe.

T. glomeratum , PM