which kind of bulbs were once exchanged as a form of currency?

Tulip bulbs were once exchanged as a form of currency during the 1600s, particularly in the Netherlands. This period is known as "Tulip Mania," during which tulip bulbs became highly valuable and were used to buy and sell goods, even actual properties. Some tulip bulbs were worth the equivalent of a year's wages or the price of a grand home. The craze reached its peak in the winter of 1636–1637 when the trading of tulip bulbs or contracts for bulbs created a speculative bubble with extremely high prices before collapsing abruptly. Tulip bulbs served not only as luxury items but also functioned practically as a form of money during this time.