Oh, rhubarb. While a stalk of asparagus or bunch of ramps may inspire foodies to rhapsodize about the promise and bounty of spring, it's rhubarb that so neatly captures the caprice and delicacy of the new season. Treat the green and fuchsia stalks right and they'll reward you with bright, sweet-tart benevolence. Do them wrong and risk the slings and arrows of sour mush. The line between edible and execrable is a precarious and fine one, and should be approached with caution.

Find an eminently edible recipe after the jump.

It looks like basil and smells like lemon, but this emerald green herb is actually a member of the buckwheat family. Native to Southeast Asia, Vietnamese coriander is used much like cilantro, its close cousin, flavor-wise. In Vietnam, it's used fresh in salads and summer rolls or cooked in soups and stews. In Singapore, it's is known as laksa leaf and is one of the main flavorings in a pungent curry noodle soup called laksa. You can find Vietnamese coriander in many Asian markets in the United States. Use it in stir fries, or try tearings bits of it into hot chicken soup with lime and chili for a pho-like flavor.

Imagine if grapefruits turned greenish, shrank to the side of golf balls and lost their hard pith. That's the duku for you. Lansium Duranum, known in various languages as langsat, lansone, kokosan, gadu guda, lon bon and longkong duku grows throughout the tropical zones of Asia. They grow in clusters on trees, and are usually bought by the bunch. To eat a duku, cut it in half and simply squeeze until the fleshy lobes pop out of their jackets. It tastes remarkably like grapefruit, though some find it even more bitter (I don't). Duku are not widely available in the US (have any of you seen them?) but are ubiquitous in Malaysia, Indonesia, the Philippines and other parts of Southeast Asia.

Pandan is the leaf of the Pandanus amaryllifolius plant. It's ubiquitious in Southeast Asian cooking, especially in desserts. Pandan is used in curries and meat dishes, wrapped around chicken and fried, used to perfume rice and to flavor cakes, ice creams and popsicles. Light green pandan cakes are a popular dessert in Malaysia and Indonesia, similar to a chiffon cake. Pandan leaves are also woven into baskets baskets, which can be used for serving food. Pandan is not readily available in the U.S., which is why it's rarely seen on menus, but can sometimes be found frozen in Asian markets.

Chestnuts, their glossy shells a reddish-brown shade that launched a thousand hair dyes, look like the acorn's voluptuous, glammed-up cousin. The starchy nut of the Castanea sativa tree, they're often viewed as a Christmas-only food in America ("chestnuts roasting on an open fire" and all that). But back in the day, chestnuts were so prevalent they were considered a poor man's food, a staple of everyday early American cooking. The nut, which matures in fall, is still used in all kinds of dishes around the world, but has become much rarer and more expensive in America due to a blight that killed off most of the country's chestnut trees in the early 20th century.

In Italy, chestnuts are ground into flour to make breads and cakes, and fermented into beer. In New England., they're sometimes still used in stuffing (check out this recipe for chestnut and mushroom stuffing).
In France, marrons glacés, or candied chestnuts are a popular winter treat, often wrapped up in frilly layers of gold and silver paper to be given as presents. In China, they're eaten roasted and salted as snacks, or used in stir-fries (see The New York Times' The Minimalist's recipe for shrimp and chestnut stir-fry).

The Jerusalem artichoke (Helianthus tuberosus L.) is not from Jerusalem, nor is it an artichoke. The tuber also known as the sunchoke is the root of a type of sunflower native to North America, and was a staple food for early European immigrants. It may have gotten its name from these pilgrims, who considered America the "New Jerusalem," or it may be a bastardization of the Italian word girasole, meaning sunflower. Once considered a "poor man's food," the Jerusalem artichoke is experiencing a bit of a renaissance as of late.

The veggie resembles a finger of ginger root, with a nutty, starchy taste, somewhere between potato and artichoke. They can be found in the produce section of some supermarkets (I've seen them lots of times, I just never knew what they were!). The Jerusalem artichoke can be used like other root vegetables such sweet potatoes, carrots and parsnips, diced and tossed in stew, roasted with herbs, or pan-fried with butter. Check out this Epicurious recipe for Jerusalem artichoke with sage butter.

A pluot is a relatively new fruit, developed in the late 20th century by Floyd Zaiger, a hybrid between a plum and an apricot that is touted by growers as having all of the good properties of both fruits, and none of the drawbacks. They have a very high sugar content, are smooth-skinned and do not have the tartness that is often associated with plum skins. Their flesh is a little bit firmer than that of plums, similar in firmness to the flesh of a ripe nectarine, so they hold up better to being eaten out-of-hand or sliced up than plums do.

While the name gets thrown around a lot, especially with the ever-increasing discussion of shopping at local farmers markets and avoiding conventionally grown, mass produced produce, many consumers still wonder what heirloom tomatoes really are.

While some feel that a set, defined time limit of 50 or 100 years must be included in the definition of an heirloom plant, the short definition of an heirloom tomato is that it is an open-pollinated tomato plant, meaning that it is naturally pollinated by exposure to birds, insects and animals. Hybrid plants, the commercially grown tomatoes, do not always produce reliable, viable seeds due to the fact that some (if not most) of the crosses used to generate the plants were done artificially.

The more traditional tomatoes, those that are often seen in supermarkets and the majority of restaurants, have been bred to enhance certain characteristics besides flavor. For example, many have been selected for disease resistance or for having a slightly thicker skin, which makes them hold up better during shipping. Most of these conventional tomatoes are close to spherical and very red in color. Their flavor is ordinary, with little "wow" factor.

Chipotle chiles are not a unique chile, but are actually dried, smoked jalapeno chiles. They are dark brown and wrinkly, in sharp contrast to the glossy look of fresh chiles, but have a wonderfully rich flavor. Most of the heat of the jalapeno is retained when the chile is dried, so chipotles are fairly spicy, falling in the middle ranges of the heat scale. They have smoky overtones, but the real flavor of the chiles is complex and earthy. Instead of causing a sharp and immediate heat, the heat grows gradually as you eat it and takes time to fade away.

In truth, most kinds of chilies can be smoke-dried and sometimes they are all called "chipotle" no matter what they started out as, but the vast majority of the chipotle chiles on the market were originally jalapenos.

While once it seemed as though the only onion options were the generic sounding yellow, white and red, each variety of onion in the market is now labeled clearly - and there are a lot of them, in addition to those three standards. But what is the difference between them? The primary difference is sweetness, with some onions, known as sweet onions, lacking the sulfuric bite that most associate with an onion.

Sweet onions usually are available in summer and have a higher water content than so-called "storage onions", which contributes to their mild flavor. It also means that they have a somewhat shorter shelf life and are more delicate, prone to bruising, than their less-sweet counterparts. They can be used interchangeably with regular onions in cooking, since they will handle almost identically, but they will impart slightly different flavors to the finished dish. Many people prefer sweet onions in dishes that call for raw onions, such as salads, or for use on burgers and hot dogs.

A woman checking out at the grocery store commented to the clerk that she had mixed emotions about Rainier cherry season. On one hand, she adored the fruits, but she said that she couldn't stop eating them. The cherries are quite expensive and, even though she was a cherry lover, she was glad that the season for Rainiers lasted a brief period so that she could enjoy looking forward to them and enjoy eating them, while not breaking the bank.

Rainer cherries are one of the sweetest, most prized types of cherries there are. They are primarily grown in California and the Pacific Northwest and are distinct from other cherries in that they have a creamy, yellow flesh and a yellow and red exterior.  While they are still one of the most popular eating cherries, some consumers are put off by their coloring, prefering all cherries to be a bright, deep red. They're missing out.

Lemon verbena is growing in popularity, seemingly by the minute. A few years ago, it was almost unheard of to the home cook, then it rapidly spread from the pages of upscale menus to Gourmet to Cooking Light and to Better Homes and Gardens. It is a perennial herb, native to Chile and Peru, that has an unusually strong lemon scent and flavor to it. The lemon scent comes from an essential oil known as citral, which is also found in lemon, lemongrass and other plants.

Verbena is not a popular herb in traditional European cookery, though it was commonly planted for ornamental reasons in European gardens after it was introduced in the 18th century. The plant grows best in temperate climates, with plenty of water and sunshine. It will produce beautiful, small flowers in the late summer and fall. Its aroma is strong and can perfume a garden easily.

Apricots are a stone fruit that has been cultivated for the past 4000 years. The originated in China, near what is now the Russia border. The tree was brought to Europe by the Romans in approximately 70BC, but it gradually spread westward through Asia over the course of s few thousand years to countries like Turkey, where it became very popular. Apricots were brought to America by Spanish missionaries.

Classified as stone fruits, apricots have a large, hard seed in their center around which the flesh of the fruit grows. They appear to be very similar to peaches and nectarines, but are often a bit smaller, measuring 1 1/2-2 1/2-inches in diameter with a prominent suture running down one side. They range in color from yellow to orange, and some varieties even have a reddish cast to them.

Watermelons hardly constitute solid food, given that they are 92% water. Nevertheless, they are kept intact by their hard, green rind and so make one of the most refreshing, healthy summer treats you can imagine.

Watermelons have more lycopene (an antioxidant) than any other fruit or vegetable, with more than four times the amount per serving than a large tomato. They are free from fat, cholesterol and are very low in calories. Though there is sugar in the melons, it is naturally diluted by the high levels of water in the fruit. Watermelons also have high amounts of vitamins A, B6, C and potassium.

The first recorded watermelons were enjoyed in ancient Egypt, approximately 5,000 years ago. Through trade, watermelons made their way to China, where they became popular rapidly, before firmly establishing themselves in Europe around the thirteenth century. Today, there are 1,200 varieties of watermelon (not counting oddly shaped ones). Some of the most popular include picnic melons, which are oblong and quite large; seedless and miniature/individual, which are growing in popularity. By and large, the fruits are juicy and sweet. Most varieties, and certainly the most popular, have red flesh, though there are types that grow with different colored flesh, such as yellow. China is still the number one producer of watermelons in the world, followed by Turkey, Iran, the US and Egypt.