The runt rules.

The citron — thick-skinned, faint of flavor, with dryish fruit, looking like a lumpy lemon — is the least-favored of all citrus fruits, but the one that gave the entire family its name.

All oranges, tangerines, grapefruits, mandarins, lemons, limes, all citrus, get their family name from the citron, despite its disfavor still grown, albeit sparely, along the Mediterranean and in the U.S.

Centuries ago, it was the first of its kind, you see, to make it from the family’s origins in Asia to Europe. Because Europe is where most of our languages’ plants names began, “citron” begat “citrus.”

The citrus family of fruits is large and influential. Indeed, it is the third largest grown after the pear and apple group (the first family of fruits) and the plantain and banana clan (the second).

Citrus can be for more than just juice

Though a third of the globe’s citrus production becomes juice, many of the individual fruits can be turned into something to eat, out of hand certainly (their most popular way down), but also as freestanding dishes of salads, macerates, and desserts. Hence, the recipes here.

Citrus go back in time 20 million years when Australia was still attached to Asia. As an edible fruit, their structure is unique: rinded, with a bitter pith, comprised of hundreds of little vesicles filled with juice, themselves corralled into separable locules (what we call the segments).

Their hues — from green, through yellow, orange and red — are a function of carotene, chlorophyll, and anthocyanin, all the same agents that color other plants.

And, unlike many other fruits such as bush berries or apples, they need warmth to flourish. The world’s largest producer of oranges is Brazil, with 30% of all oranges raised. Of tangerines (mandarins), China. And of grapefruit, the United States.

An important member of the citrus family is Citrus reticulata, what we know as “mandarin oranges,” or tangerines, or “Clementines.” They are small, generally quite sweet (which is to say, lower in acidity than typical lemons or limes), easily peeled and noticeably segmented.

The clementine is a cross between the mandarin (a small orange brought to England from China in 1803) and the larger sweet orange. They obtain their name from a monk named Marie-Clément who hybridized them in Algeria around 1900. They’re not named after the song “Oh, My Darling Clementine,” nor is the song named after them.

Tangerine is simply an alternate nickname for the mandarin, given to it by North Americans who assumed that the mandarin, when introduced into the United States in the late 1800s, came from Tangier, Morocco.

What citrus offers to all cooking, above all, is acidity, the sour or puckery sensation that juices up the palate with saliva and for which function all acidity is rightfully praised in culinary art. Unlike salt, which enhances flavors, acidity balances them. For example, either sweetness or fat, if alone in a dish, may be delicious but also will appear dull after several tastes. Citrus renders those tastes more lively and enticing if it is present.

If anything is too “plain” in your food—too starchy, perhaps, or too monochromatic—a mere whisper of acidity (a squeeze of lemon, a dash of vinegar, a spoonful of white wine) will bring it to a life you could not imagine it had within it.

When cooking with citrus, try these recipes.

Orange Salad (Ensalada de Naranja)

From Claudia Roden, “The Food of Spain”; serves 4

Ingredients

2 oranges

1 small head romaine lettuce

1/2 sweet red onion, finely chopped

3 tablespoons extra virgin olive oil

1 tablespoon sherry vinegar

1 tablespoon port or sweet Pedro Ximenez wine

Salt

Directions

Peel the oranges so that no pith is left, and cut them into slices crosswise. Cut the lettuce into wide strips. Arrange the lettuce and oranges on a platter and sprinkle on the onion.

Just before serving, beat the olive oil, vinegar, wine, and a little salt with a fork and pour over the salad, then gently toss the salad.

Any-Other-Citrus Vinaigrette

From Samin Nosrat, “Salt, Fat, Acid, Heat”

Ingredients

1 tablespoon finely diced shallot

4 tablespoons white wine vinegar

1/4 cup citrus juice

1/4 cup extra virgin olive oil

1/2 teaspoon finely grated zest

Salt

Directions

In a small bowl or jar, let the shallot sit in the vinegar for 15 minutes to macerate, then add the citrus juice, olive oil, zest, and a generous pinch of salt. Stir or shake to combine, then taste with a leaf of lettuce and adjust salt and acid as needed.

Cover and refrigerate leftovers for up to 3 days. Ideal for garden lettuces, romaine and Little Gem lettuce, and blanched asparagus.

You may reach Bill St John at [email protected]