The structure of the fetus, seed, embryo of 3 species of ephemerals of the genus Alyssum, collected in the southwestern Kyzylkum, is described. Fetus of the Alyssum species is rounded, wide-pated silicle, with fetus stems of a truncated-conical (A. dasycarpum) shape. Pericarp is 4 - 5 layered. The fetus is seedless (2 - 4), and the seeds are protein-free, with a large embryo. At the general plan of a structure, species have diagnostic signs distinguishing them on the form of a fetus, weight of seeds, the structure of embryo mesophyll.