The results proposed here and by Dunbabin (2001) for capeweed (Arctotheca calendula) and Bennett (Bennett, 2001) for colonising clover (Trifolium) species in Western Australia, suggest that this advantage may be much <previously supposed.
In capeweed, Dunbabin (2001) found a negative correlation between plant size and length of growing season, which he considered to be an adaptation to the more intensive grazing pressure likely to occur in high rainfall areas.
Pasture sites were managed according to standard agricultural practices in the region (Squires and Tow 1991) and were dominated by annual species, such as subterranean clover (Trifolium subterraneum) and capeweed
(Arctotheca calendula), along with a range of grasses.
Many of these plants are still sold by California nurseries and planted by California gardeners, whose back yards serve as springboards for the spread of Cape ivy, capeweed
, vinca, broom, iceplant, English ivy, passionflower vine, pampas grass, and acacia.
A mixture of diquat (112 g/ha) and paraquat (187 g/ha) was applied on i 6 June 1999 to control radish (Raphanus raphanistrum) and capeweed
Many sites in the winter rainfall zone (1, 2, 4, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18) also had a reasonable presence (>10% on a dry-weight basis) of annual winter-growing annual grasses [mainly brome grass (Bromus spp.), silver grass (Vulpia spp.), barley grass (Hordeum leporinum Link), or annual ryegrass (Lolium rigidum Gaudin)] and capeweed
(Arctotheca calendula L.).
In Australia, the highest Cd concentration is found in capeweed
(1.57 mg Cd/kg), a species that can also be present in New Zealand pastures.
Furthermore, non-leguminous species, such as capeweed
(Artotheca calendula) and annual ryegrass (Lolium rigidum), are major components of pastures in southern Australia (Rossiter 1966).
An annual pasture consisting of varieties of subterranean clover (Trifolium subterraneum) was sown in June 1994, and capeweed
(Arctotheca calendula) also became a major pasture component.