Mustard Seeds - Kobu Horned. Heirloom. Brassica juncea var. linearfolia. 45 days. This Chinese mustard is a vigorous grower with bright green, frilled leaves and mustard pungency. The rare plant species forms a distinct "horn" in the center of its stem. Used for pickling or stir-frying, this native of Southern China also has delicious bud shoots. ~18,400 seeds / oz.