Aurinia saxatilis subsp. arduini 

This Aurinia is from Czech collected seed. 0-35 cm, sunny dry place, poor rocky soil, good drainage.  To quote the marvellous  Robert Nord, "Aurinia saxatilis, the basket of gold alyssum... is the most drought-tolerant plant I have ever grown, including cacti. Only a stone is more drought-tolerant. It will seed freely and form attractive clumps of grey-green leaves that look nice under shrubs."