Wild yellow carnation (Dianthus knappii) belongs to the Caryophyllaceae (the Carnation family). It is a perennial herb that is native to eastern and central Europe. This herb has finely downy, grass-like foliage ant it can reach about 40 cm in height. The flowers are light yellow, relatively small, at 2 cm in diameter, and it blooms in tight clusters though much of the summer. The photos are a cultivated variety 'Yellow Harmony'.