Trillium

Trillium is a substance (probably mineral) that is regularly being traded in the 23rd and 24th century.

In 2267, Spock posed as a trader of kevas and trillium while on Organia. (TOS: "Errand of Mercy")

Later, in 2373, Arne Darvin made the same claim while aboard the USS Defiant. (DS9: "Trials and Tribble-ations")

In the novelization of "Errand of Mercy" in Star Trek 2, Spock described trillium as "a medicinal plant of the lily family", as in the real-world trillium.