Umbilicus oppositifolius commonly known as lamb's tail or gold drop is a succulent, perennial flowering plant, a species in the genus Umbilicus of the family Crassulaceae. It is endemic to shady mountain areas in the Caucasus.
It is widely listed under its synonym Chiastophyllum oppositifolium.
It is a hardy, prostrate evergreen growing to 25 cm (10 in) with large fleshy leaves and racemes of tiny, sulphur-yellow flowers.
It has gained the Royal Horticultural Society's Award of Garden Merit.