By 9 a.m. on Tuesday, the day after Yom Kippur, the corner of Essex and Canal Streets on New York’s Lower East Side was coming to life, as vendors on different corners set up makeshift tables. They proceeded to display the fruit, leaves, and branches that comprise the biblically mandated Four Species—myrtle, lulav or date palm, willow, and citron for sale in advance of the Feast of Tabernacles, the seven-day harvest and ingathering feast better known as Sukkot. By midday, the scene would be a hectic bazaar of examining and bargaining by finicky customers, as it would be the rest of the week. Many of the customers have for years patronized the wares of 67-year-old Ezra Shoshani, a stocky vendor and longtime waiter at the late-lamented Ratner’s dairy restaurant, whose 33-year-old son, Yosef, is a rabbi at the nearby Eldridge Street Synagogue.Of those Four Species, none gets more critical appraisal than the fragrant and sunny lemon-lime green citron, Citrus medica—or, in Hebrew, etrog—is a symbol of human fertility. “It’s so important that it be right,” said Yosef Shoshani, “that in Hasidic Brooklyn communities like Williamsburg and Borough Park, the sale begins right after Rosh Hashanah. Each customer can get permission from a vendor to take the etrog to a rebbe for inspection. They have plenty of time there for things like that. Prices there for the same etrogs we sell can be three or four times as much because many vendors pay a rabbi to stay on site for lengthy appraisals.”Shoshani explained just why a citron can range in price from about $30 to as high as $100 (or even $1,000 for a specially sought out example). “It must be freshly picked, with a regular, pleasing oval shape, and its knobby skin must be as perfect as possible,” he said. “To be sure of that, one looks through a magnifying loupe, watching for bruises or schwartze pimpele, black pimples or specks. It’s something like glatt for kosher meat; there must be no bruises or lesions. Most of all, its pistil end, the protruding nipple, known as the pitom, must be intact. If that has fallen off while the fruit is still growing, the citron is acceptable. But if it falls off after picking, the citron is pasul, invalid.”The rules for the Four Species are laid down in Leviticus 23:39-40. “And you shall take on the first day the fruit of a beautiful tree, [pri etz hadar] date palm fronds [lulav], a bough of a leafy tree [hadass or myrtle] and willows [aravah] of the brook; and you shall rejoice before the Lord your God seven days.” The Talmudic sages determined the exact identities of the mandated Four Species. In trying to determine what specific fruit was alluded to, they considered the citron, the pomegranate, and the carob. The pomegranate, they decided, was glorious but its tree was not, and the carob tree was glorious but the fruit was not. With its luminous green-to-sunny yellow mottled rind, its elongated oval shape that makes it felicitous in the hand, and the exotically spicy, lemony perfume it exudes as it ripens, the citron was the clear winner.There are exacting features for the other three species as well. The myrtle, promising long life and success, must have a red stem with sets of three leaves growing from each node. The lulav, a symbol of victory over enemies, sheaves from the heart of the date palm and must be attached to the central stem. Willows, symbolizing life-essential water, must stand upright, proving they are not wilting because of dehydration.The number four itself is significant and denotes the most important parts of the body—eye, lips, heart, and spine—as well as the four directions: north, south, east, west. Maimonides said the four species remind us of the joy the Israelites felt in leaving the barren desert where none of these plants could grow for deliverance to the fertile Promised Land where they all flourished.Those who can afford to hang a citron in the sukkah, the leaf and fruit-decked temporary dwelling erected during Sukkot. Because the citron’s inner flesh is dry and pulpy with only a rather pallid lemon-lime flavor, it’s no wonder few bother to prepare it for eating after Sukkot. The thick, resinous rind is another matter entirely, and ambitious home cooks simmer it with sugar to attain a rich, bitter-sweet marmalade. Commercially, the citron’s rind is valuable as it is candied and diced to add a limpid green-gold, jeweled note and an enticingly pungent zest to holiday breads and fruitcakes as well as to confections such as marzipan or nougat and festive cold rice puddings.Jews are not the only ones to project symbolism onto the citron. “The fruit seems always to have had a curious connection with religion, medicine and magic,” writes Alan Davidson in The Oxford Companion to Food. Ancient Greeks called the citron the Persian apple and tucked it among woolens to discourage moths. And in India, Kuvera, the Hindu god of wealth, is always shown holding a citron in one hand. India, in fact, is believed to be the original home of the citron that then traveled to Persia and Babylon, where displaced Jews discovered and embraced the fruit, later taking seeds and cuttings with them back to Palestine.The most expensive citrons, according to Shoshani, are the silver-green specimens grown in Italy, followed by those from Israel and Morocco. Cheaper ones from Corsica and California are available as well. They are typically sold in cardboard carrying boxes lined with soft plastic, but far more highly prized, and priced, are the elaborate citron-shaped cases in sterling silver or vermeil, gold-plated silver. These elegant citron boxes are lined with velvet or silk and would surely be the choice of the god Kuvera. Considering the exacting guidelines for choosing the four species, it is strange that they sell well on the internet. Apparently those far from etrog markets are willing to trust the gods of cyberspace.Mimi Sheraton is a former restaurant critic for The New York Times and the author of several books including The Bialy Eaters.