Whilst on a touristic visit in Carthage today, I came across this plant and took a sample. Later at home, my husband showed me how to identify it with the help of his modest reference library of botanical books.
Figure 1: Lobularia maritima
It is also known under the name of Sweet Alyssum. "Sweet Alyssum is a very adaptable plant that forms mounds covered in fragrant flowers. The modern hybrids are dwarf, compact and come in a range of colours, including pure white, purple and rose. They will grow easily from seed, flowering within six weeks of germination and, with occasional watering, will continue to flower until the early frosts; in mild areas, alyssum is perennial, though shortlived." Extract taken from The Mediterranean Gardner by Hugo Latymer.