When we first arrived in Costa Rica and went to the supermarket to buy groceries, I noticed that next to the ‘normal’ limes there was another variety. To be honest, at first they sort of looked like reject limes, since their zest was pockmarked, like my early pubescent face with acne. However, I always love to try new foods and ingredients, so I bought a few, and I have been obsessed with them ever since.

The first thing I noticed is that instead of a light-green color inside, they are bright orange.

Some quick online research showed that they are the variety ‘Limón mandarina’, or ‘Mandarin lime’. They are also known as Rangpur, from the region of Bangladesh known for citrus fruits, and if left to mature the exterior will become orange as well. Apparently they are originally from India and were introduced to Florida in the late nineteenth century. I haven’t found how they came to Costa Rica, but it seems that this is one of the only places where they are widely grown commercially.

While frequently described as a cross between a lime and a Mandarin orange, genetic analysis shows that they are the descendant of a Mandarin orange and a citron, the forbearer of lemons and the same family as the fun-looking Buddha’s hand citrus. If you want to nerd out, there is an open-source Nature article from 2018 that traces the origin and spread of different citrus fruits from their genetic origins. It reminds me of ten years ago when I was living in Seattle, and I heard everyone talking about Marionberries (before the Portlandia episode made them more well known). In trying to figure out what they were, I came upon this chart:

Being a total agriculture and botany novice, I had no idea that they were created at Oregon State University in the 1950s and have their own genealogical tree. Like learning about how varieties of many fruits are just grafts from other plants, instead of arising from seeds, in Michael Pollan’s The Botany of Desire, I similarly had one of those Singer-esque, coffee-drop moments.

Much like the biodiversity that I have witnessed here on vacation, I’m constantly amazed at how much there is to learn about the vastness all around us.

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For breakfast, I’ve been juicing mandarin limes over papaya and other fruit, spiking up the citrus zing.

For a beach lunch, they help liven up rice and beans (gallo pinto, though I’ll admit ours is not authentic) and avocado, and an Imperial with mandarin provides a refreshing twist on the Corona and lime classic.

And for dessert, pan-caramelizing them adds some sweetness and depth of flavor to the juice that pairs perfectly with fried plantains and pineapple sprinkled with sugar.

Tonight, we’ll experiment with some rum-based cocktails. It is impressive how adding new ingredients can lend familiarity while adding an element of novelty to many dishes. René Redzepi and the Noma staff are experts in using new, local elements (among many other skills), but in looking at the list of citrus fruits used worldwide, yuzu jumped out as a recent ubiquitous addition to upscale restaurant cuisine. Maybe in a year or two, every hipster restaurant will be proudly displaying ‘limón mandarina’ on their menus. I’m more than okay with that. The more culinary diversity we have, the better.