Garden cress (Lepidium sativum) or cardamom (Elettaria cardamomum). Both come from the Greek word κάρδαμον (kardamon) which goes back to ancient Minoan Linear B. Greeks put the cress in salads.
The south Asian spice, which the botanist Theophratus knew about in the 4th century BC (perhaps Alexander's army brought back a pod or two back to Greece). He even knew of the difference between the two kinds of cardamom, the green (Elettaria cardamomum) and the black (Amomum subulatum), which derived its scientific name from the ancient Greek ἄμωμον. For all that, it rarely appears in traditional Greek dishes.
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