Cauliflower

• 1. Introduction

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  Cauliflower hides a secret in plain sight. The dense white dome we slice apart in the kitchen is not a root, not a fruit, and not really a flower. It is a head of undeveloped flower buds, a structure botanists call the curd. The name comes from a similarity in appearance to cheese curd. This vegetable carries the scientific name Brassica oleracea var. botrytis, and it shares that species with cabbage, broccoli, Brussels sprouts, kale, and kohlrabi. So how did a single wild plant give rise to forms this different? Why does one variety, the Romanesco, grow its curds in spiraling fractal patterns precise enough to interest mathematicians? And how did a vegetable once linked to a single Mediterranean island end up grown across the world, with China and India alone accounting for most of it? The answers run from antiquity to a mutant discovered in a Canadian field.

• 2. An Arrested Flower

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  The curd is the whole point of cauliflower, and it exists because the plant was bred to stop. Cauliflower is described as an arrested inflorescence, a flowering structure frozen before it can bloom. Genomic analysis suggests it first evolved from broccoli, with three MADS-box genes playing roles in how the curd forms. Nine loci and candidate genes are linked with its morphological and biological characters.

  The edible portion is that dense head of undeveloped flower buds. When cooks prepare it, they strip away the outer leaves and thick stalks, leaving only the florets, though the leaves themselves are edible and merely tend to get discarded. White is the usual color, but the head can also appear green, orange, or purple. Each of those colors traces back to a different cause, and the orange one began as an accident no breeder planned.

• 3. Colors From Mutation

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  Orange cauliflower owes its hue to a natural mutant found in a cauliflower field in Canada. The pigment is beta-carotene, a provitamin A compound, and it survives today in cultivars such as 'Cheddar' and 'Orange Bouquet'. A single chance plant in a field became a commercial line.

  Purple cauliflower takes its color from anthocyanins, water-soluble pigments also found in red cabbage and red wine. Varieties include 'Graffiti' and 'Purple Cape'. Green cauliflower, sometimes called broccoflower, has been commercially available in the United States and Europe since the early 1990s, both in the normal curd shape and as the fractal-spiraled Romanesco. Green-headed varieties include 'Alverda', 'Green Goddess', and 'Vorda', while Romanesco varieties include 'Minaret' and 'Veronica'. White remains the most common, its pale head set against surrounding green leaves.

• 4. Cyprus And The Sun King

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  In the Middle Ages, early forms of cauliflower were tied to a single place: the island of Cyprus. The 12th- and 13th-century Arab botanists Ibn al-'Awwam and Ibn al-Baitar both claimed Cyprus as the vegetable's origin. The link held so firmly that cauliflowers were sometimes called Cyprus colewort in Western Europe.

  Under the French Lusignan rulers of the island, a brisk trade in cauliflower seeds flowed from Cyprus into Western Europe, continuing well into the 16th century. The plant is thought to have reached Italy from Cyprus or the eastern Mediterranean coast around 1490, then spread across Europe in the centuries that followed. France received it from Genoa in the 16th century. Olivier de Serres described it in his Théâtre de l'agriculture of 1600 as cauli-fiori, calling it still rather rare in France and giving it an honorable place in the garden for its delicacy. François Pierre La Varenne later used chouxfleurs in Le cuisinier françois. Yet it did not commonly appear on grand tables until the time of Louis XIV.

• 5. Four Great Groups

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  Pliny the Elder may have eaten an ancestor of cauliflower nearly two thousand years ago. In his Natural History he praised a plant called cyma: "Ex omnibus brassicae generibus suavissima est cyma", meaning "Of all the varieties of cabbage the most pleasant-tasted is cyma". His description likely refers to the flowering heads of an earlier cultivated form of Brassica oleracea.

  From such beginnings, four major groups eventually took shape. The Italian group is the ancestral form from which the others were derived, diverse in appearance and including white, Romanesco, and brown, green, purple, and yellow cultivars. Northern European annuals were developed in Germany in the 18th century for summer and fall harvests, including the old cultivars Erfurt and Snowball. The Northwest biennial group was developed in France in the 19th century for winter and early spring harvest, with the cultivars Angers and Roscoff. The Asian group, a tropical type, was developed in India during the 19th century from the now-abandoned Cornish type and includes Early Benaras and Early Patna. The British had introduced cauliflower to India in 1822.

• 6. The Difficult Crop

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  Cauliflower is relatively difficult to grow compared to cabbage, prone to an underdeveloped head and poor curd quality. Weather is the limiting factor. The plant grows best in moderate daytime temperatures, with plentiful sun and moist soil high in organic matter. Long stretches of sun in hot summer weather can turn heads a red-purple hue.

  The earliest maturity possible is 7 to 12 weeks from transplanting. Field seedlings are shallow-planted and thinned to roughly 12 plants per foot, with ideal growing temperatures near 65 degrees Fahrenheit when seedlings are 25 to 35 days old. Transplanting to the field normally begins in late spring and may continue into mid-summer.

  Once growing, the crop faces a long list of threats. The most important quality disorders include hollow stem, stunted head growth or buttoning, ricing, browning, and leaf-tip burn. Major pests include aphids, root maggots, cutworms, moths, and flea beetles, while diseases include black rot, black leg, club root, black leaf spot, and downy mildew. When the head finally appears clear white and compact, it should be cooled shortly after harvest, with forced air cooling sometimes needed during hot weather. Pollination, meanwhile, comes from an unglamorous helper: many species of blowflies, including Calliphora vomitoria.

• 7. A Vegetable Reinvented

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  Twenty-five calories sit in a 100-gram serving of raw cauliflower, which is 92% water, 5% carbohydrates, 2% protein, and almost no fat. It carries a high content of vitamin C at 54% of the Daily Value, with moderate levels of several B vitamins, vitamin K, and potassium. The cabbage family also gives it phytochemicals such as isothiocyanates and glucosinolates, under preliminary research. Boiling reduces glucosinolate levels, while steaming, microwaving, and stir frying do not significantly affect them.

  That low-calorie, gluten-free profile drove a recent reinvention. Cauliflower rice is made by pulsing florets and cooking them in oil. Cauliflower pizza crust comes from cauliflower flour, and mashed cauliflower stands in as a low-carbohydrate alternative to mashed potatoes. The numbers reflect the shift. Between 2012 and 2016, cauliflower production in the United States rose by 63%, and cauliflower-based product sales climbed 71% between 2017 and 2018.

• 8. Fractals And Boxers

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  Mathematicians have measured cauliflower and found a fractal dimension of roughly 2.8. Every branch, or module, resembles the entire cauliflower. As the modules grow more distant from the center, the angle between them equals 360 degrees divided by the golden ratio, a pattern shared with other plant species and seen most vividly in the Romanesco, whose spiral curds grow in fractal patterns.

  The vegetable lent its shape to human anatomy too. A boxer's swollen, deformed ear was thought to resemble a cauliflower, which is how the term cauliflower ear entered the language. The word cauliflower itself comes from the Italian cavolfiore, cabbage flower, rooted in the Latin caulis for cabbage and flos for flower. A flower that never blooms, named for the bloom it withholds.