Lucky four-leaf clovers

Despite being linked with spontaneous luck, four-leaf clovers don’t happen by chance. There are genetic causes for the once-in-a-blue-moon occurrence, even if scientists haven’t figured out exactly what they are.

Of the more than 300 clover species, the widespread white clover is the most likely to have a fourth leaf. It’s a bit complicated, but what’s interesting is that the fourth leaf may be linked to the number of chromosomes the clover has: twice as many as humans, mangoes and most other organisms.

The white clover is native to three continents, and its genome tells the story of a plant that geography tried, and failed, to split into multiple species.

First, you shouldn’t use ‘shamrock’ and ‘clover’ interchangeably.
Especially if you’re around some seriously Irish people. All shamrocks are clover, but not all clovers are shamrocks. Shamrock comes from the Gaelic word seamrog, which means “little clover,” but no one — not even botanists —is sure which species of clover is the “real” shamrock. In 1988, botanist Charles Nelson did a shamrock survey for his book “Shamrock: Botany and History of an Irish Myth.” The Trifolium dubium, or lesser trefoil, was the most common response.

You can grow clover indoors.
Many of the clover plants you see in stores are species of oxalis (wood sorrel) family, which are easier to grow indoors. The oxalis family has more than 300 species including Oxalis acetosella, also called the Irish shamrock, and Oxalis deppei, known as the good-luck plant. Shamrock plants need direct sun, barely moist soil and cooler temperatures.

The four-leaf clover is a well-known logo.
In the late 1890s and early 1900s, rural youth clubs were formed across the U.S. to give kids a better agricultural education. Early on, they used a three-leaf clover as their symbols with each leaf representing head, heart and hands. A fourth leaf was added and the club became known as 4-H. The fourth “H” momentarily stood for “hustle,” but then was replaced with “health.”

Clovers can grow many more than four leaves—the Guinness record is 56 leaves on a single stem. Speaking of Guinness, if you drink enough of it today* you’re sure to find plenty of six-leaf clovers, at the very least.