Mystery Plant! #701

John Nelson

Posted December 29, 2022

By John Nelson

Some of my best botany field trips have been to supermarkets and produce stands. There’s always something interesting to see, and it makes an easy way of bringing classroom botany close to home (and the kitchen). Now, I’ve never taken one of my classes to a European city for a late-year visit to one of the famous farmers’ or Christmas-time markets, but I bet it would be fun.

Photo by John Nelson

Now in Vienna, the big city market is the place to be for produce. For a while now, and even beyond the Christmas season, one can see crates of this odd fruit for sale. It is sold as something of a confection. It is probably not quite as popular as a seasonal treat now as it was a few decades ago, but it remains a charming curiosity that is fun to play around with.

These pods are indeed beans, the fruits of a red-flowered, evergreen tree that is native to the Middle East, well into Turkey and Saudi Arabia. It has been known and used since the time of the Egyptian pharaohs, and was spread around by the Greeks. The Romans were fond of it, too: pods have been recovered from the ruins of Pompeii. This drought-resistant species is now cultivated as far west as Spain, and is grown in a few places in the southern United States. The shiny, purple-brown fruits are elongated and flat, but they tend to curl, somewhat resembling a goat’s horn (the scientific name comes from a Greek word which means “horn.”) The beans have been used for thousands of years as a fodder for cattle and goats. Each pod contains a dozen or so seeds, which are surrounded by a sweet, edible pulp. This pulp is quite fragrant–pleasantly–and provides a chewy, although a bit messy, snack. Mixed with chicory, the pulp makes a coffee substitute, but its most important use, by far, is as an excellent chocolate substitute. The seeds themselves are useful, too, providing an important gum source, which is used in food additives, cosmetics, adhesives, and as a binding component of match-heads.

As a member of the legume family, this plant is related to various species known as “locusts.” One of the common locusts of eastern North America is “Honey locust,” a previous, thorny subject for this column, and a species which also has elongated, flat, curling pods.

But back to the market-place in Vienna. The German name for our Mystery Plant is “Johannisbrot,” which means “John’s bread,” a direct allusion to the bible story of John the Baptist. Roaming around in the wilderness, there weren’t many fast-food joints to visit, so he would have had to do what he could, perhaps subsisting, as they say, on “locusts.” There is considerable controversy as to whether he would have been eating the insects, or indeed, the pods of this tree, which would have been on hand. 

[Answer: “Carob,” Ceratonia siliqua]

John Nelson is the retired curator of the Herbarium at the University of South Carolina, in the Department of Biological Sciences. As a public service, the Herbarium offers free plant identifications. For more information, visit or email

This content is being shared through the S.C. News Exchange and is for use in SCPA member publications. Please use appropriate bylines and credit lines.