This is a member of the daisy family (Asteraceae) and is native to Europe and western Asia. It forms a mound of attractive finely dissected leaves, smothered in brilliant yellow daisies from mid-spring until summer. It grows about 50-90 cm in height but will also cascade over a garden wall quite effectively. It will grow over a wide climate range, from very cold areas to warmer zones, including Sydney. It is important to give it excellent drainage and a full sun position, and not to allow other plants to crowd it out. Prune back hard after flowering to promote more compact growth, and fertilise in late winter.
The plants form a clump and detached rooted pieces from the edge of the clump can be used for propagating it. It is wise to replace the original plant with a new one every so often, as they get exhausted after a while. It looks good combined with bright blue Salvia specimens or with hot-coloured flowers such as Dahlia and Canna. There are a number of named cultivars, with colours ranging from cream to orange-gold, but I have had most success with the basic species. The flowers are useful for vases, lasting for quite a long time. In the garden, the blooms attract beneficial insects, including bees.
Postscript: my plant eventually faded away as I didn't get round to propagating a new one before it got too old! I hope to grow it again some day.