is a specific kind of: crucifer, cruciferous plant.

is a broader term that covers: watercress | Arabidopsis thaliana, mouse-ear cress | Arabidopsis lyrata | rock cress, rockcress | Arabis glabra, tower cress, tower mustard, Turritis glabra | scurvy grass, St. Barbara's herb, winter cress | bitter cress, bittercress | Cochlearia officinalis, common scurvy grass, scurvy grass | common garden cress, garden pepper cress, Lepidium sativum, pepper grass, pepperwort.

is a member of: Brassicaceae, Cruciferae, family Brassicaceae, family Cruciferae, mustard family.

is a specific kind of: salad green, salad greens.

is a broader term that covers: watercress | garden cress | winter cress.