(Lactuca sativa— Family Compositae)
Garden lettuce is believed to be a selected form of the bitter-leaved wild species (Lactuca serriola)
found throughout Europe, Asia, and North Africa.
The ancient Egyptians were said to have been the first to cultivate it. There are examples of tomb paintings which depicted a form of Cos lettuce said to have originated on the Greek island of the same name.
The Egyptians believed it was an aphrodisiac. They also used its white sap and leaves in a concoction along with fresh beef, frankincense, and juniper berries as a “remedy” for stomach aches.
The Romans also attributed medicinal properties to the lettuce, and the Emporer Augustus erected an altar and a statue in its honour. The Romans are said to have introduced it to Britain by their conquering armies.
The wild lettuces were harsh and not normally eaten as they contained a latex with a mildly soporific effect, which may have explained its numerous “medical” uses. The bitter lettuce had more of the narcotic substances; but, by 1600, these effects had been greatly reduced.
The Roman name for lettuce was lactuca, indicating its milky sap or latex
which was associated with milk, lac, but smelled like the latex of opium poppies, although they are not related.
During this time, lettuce was eaten at the end of the evening meal so as to induce sleep. Later, it was eaten at the beginning to stimulate the appetite. It is amazing how such a reversal could have occurred within the breeding processes of one plant.
Some of the historically medicinal uses include the following:
- a mild sedative
- a mild narcotic
- in a soup, effective in treating nervous tension and insomnia
- the sap dissolved in wine and used as a painkiller
- used in creams to soothe inflammation of sunburns and rough skin
- as a poultice on bruises
- taken internally for stomach ulcers and irritable bowel syndrome
- as an antispasmodic
- cough and bronchial soother
- used to cool ardour (not sure if that was before or after its supposed aphrodisiac effects)
By the 1st century CE, Pliny was mentioning nine varieties of lettuce, including a purple one
and a red one.
All were looseleaf types.
By the 5th century, lettuce was being cultivated in China, where it was treated as a vegetable to cook. Because of this, the types of lettuce developed in China and the Far East have different characteristics from the European types.
Following the Dark Ages, lettuce does not appear again in literature until Chaucer’s 14th century Canterbury Tales. By the 16th century, head lettuce was being developed.
17th century writers mention cut leaf, oak-leafed, and those with multiple heads like brussels sprouts.
Various colours were also appearing, including light green, dark green, red, and spotted; and some have been revived today.
Seeds from European lettuces were taken to the Americas as early as 1494, and all the American lettuces have that European ancestry. There are native wild types, however, including the Canada wild lettuce (L. canadensis).
Indian lettuce (L. indica)
is a variety from China, and not India.
It belongs to a different species and has been developed separately from the sativa varieties, but not yet officially recognized. It is rather coarse, with reddish leaves, or leaves with a red midrib. It is an upright-growing perennial that can reach heights of over four feet. Grown mainly for its leaves and cooked as a vegetable, it is now cultivated in Malaysia, Indonesia, Japan, the Philippines, and Taiwan; but is largely unknown in the West.
Tsitsa is a common Japanese lettuce,
and has been independently domesticated from a different wild lettuce.
Lettuces cultivated outside can weigh as much as a pound, while those grown under glass are sold at weight of about four ounces and up.
Insufficient head formation or hearting is a typical characteristic of winter lettuces, and happens when greenhouse-grown types fail to develop firm heads because of a lack of adequate light or warmth. The “head” is often held together from only its plastic bag and withers more quickly.
This is why greenhouse produce is sometimes sold in plastic bags so as to prevent excessive evaporation. A further disadvantage is that in winter, head lettuce often contains higher levels of nitrates which amass in the plant, particularly when there is too little light during growth.
also loses freshness quickly, especially when it is stored unwrapped and in warm conditions. They are very sensitive to ethylene, a gas given off by ripening fruit, during storage. Ethylene causes reddish-brown spots to appear on the leaf ribs and speeds up spoilage.
Therefore, lettuce should be stored away from fruits, including tomatoes; but consumers do not have any such control behind the scenes in the supermarkets.
There are four main types of lettuce: crisphead, butterhead, looseleaf, and cos all with hundreds of varieties in each:
Crisphead lettuces are the ones with crunch. Iceberg
is the most popular variety, but also the biggest nutritional loser among lettuces.
Its crisp compact leaves form a tight head, and the colour ranges from white in the interior to pale or medium green on the outside.
New varieties include red-leafed only, or red and green-leafed combined, all of which have a mild bland flavour. It can be cut or shredded like a cabbage and can withstand thick salad dressings.
As early as the 1920s, crisphead lettuces were transported great distances across the US; and rail cars were piled high with ice to keep them fresh, hence, the name “iceberg”.
Iceberg lettuce can weigh up to three times as much as butterhead lettuce because it is much more densely packed and crunchier. It is also far less perishable than butterhead lettuce and can be stored in the refrigerator for up to two weeks, if stored in plastic.
Crisphead lettuces may have very diverse leaf structure and head formation, depending on their origin and type. Crispsalat was once only grown in Holland, but always under glass. It has three or more wrapping leaves and a spherical heart. Another type, calledkrachsalat is generally sold at farmers’ markets, and in Switzerland.
Red crisphead lettuce
has only recently been cultivated in any significant quantity compared with green varieties.
Batavia is a crisphead lettuce developed in France, and now grown outdoors in Italy and Western Switzerland, but in greenhouses in Holland and Germany. Although it looks like an iceberg, it is curlier and less crunchy. The colour can vary from a dark reddish brown to a light green with red edges.
A curly lettuce is a new Dutch cross between crisphead and butterhead lettuce and marketed in Europe. It has a slightly sweet flavour. Other varieties of Crispheads include Avoncrisp, Malika, Premier Great Lakes, Saladin, and Webb’s Wonderful.
have the softest leaves among all lettuces and are tender, almost floppy, forming a loose but pretty head. Boston resembles a flowering rose, while bibb has a smaller, cup-shaped head. The leaves come in green, red, or bronze. Its soft buttery texture and sweet flavour makes it a good companion for stronger tasting greens. Butterhead varieties also include the cabbage type lettuces. The following varieties are popular: Action, All Year Round, Avondefiance, Bibb, Buttercrunch, Dolly, Kwiek, Limestone, Musette, Red Tip, Sabine, Sangria (tinged with red), Soraya, and Valdor.
are sometimes called “cutting”, “bunching”, or “curled” lettuces (var. crispa) because they do not form a head, but rather a loose bunch of leaves.
There are many different variations in colour and shape. Leaves may be round or elongated, indented or with unbroken margins, and the plant ranges from low and bushy to upright. The fully grown leaves are either cut or picked individually, making a number of harvests possible.
In commercial harvesting, the whole bunch is cut rather than individual leaves. This type is a favourite of home gardeners as it can be picked all summer long. Once a leaf is picked at the stem, a new one grows back up again.
This type has numerous varieties many of which are grown as baby lettuces.
Some varieties are: Oak leaf, Grand Rapids (crinkled pale green leaves with bronze-green to crimson edges), Ruby (crinkled and pale green with deep red tints), Salad Bowl (one of the first leaf lettuces, having masses of green, deeply lobed leaves that are crisp but tender), and the elongated Deer Tongue.
Their flavours range from mild to sweet to woody. Colours vary from pale to dark green, deep crimson, or bronze. Leaf shapes also vary from oval or oak-leafed, smooth, puckered, deeply curly, ruffled, or frilly.
The Italian varieties Lollo Rosso (red lollo) and Lollo Biondo (green lollo) can be treated as cutting lettuce throughout the summer; or the whole plant can be cut, making just one crop possible. Both varieties taste pleasantly strong and nutty although slightly bitter. This type of lettuce actually belongs to the cutting or looseleaf variety, but their tightly crimped tender leaves form such a compact hemispherical rosette that they give the impression of a head.
Cos or Romaine lettuces (var. longifolia)
have long upright leaves that form a cylindrical head. They are probably not named for the island of Cos, but from the Arabic name word for lettuce.
The name Romaine may have been given because these lettuces reached western Europe through Rome. This type is most common in the Middle East because of its tolerance of hot climates. The leaves are generally green, but can be found in red and have thick, crisp, juicy ribs.
Its strong texture stands up to cooking better than any other lettuce, and the flavour is sharper and pleasantly nutty. Because of their curly leaves, they do require extra washing.
Romaine is the most nutritious of the lettuces and a good source of folate, vitamins A and C, calcium, iron, and potassium. Leaves with the darkest green will have more nutrients than the paler ones. The whiter parts are virtually nothing more than traces of fiber and water rather than nutrients.
Belonging to the long group of lettuces, romaine lettuce grows upright to a height of about sixteen inches and has elongated leaves with rounded tips; but, depending on the variety, the heads can also be rounder or more oval in shape. The outer leaves are darker, while the inner ones are more delicate and blanched a yellowish white.
Older varieties have to be tied together to blanch the inner part, but newer types are self-blanching. They also take longer to mature and better suited to cooler weather.
Romaine and cos lettuces have slightly coarser and firmer leaves and keep better than head lettuce; but, unlike other lettuces, can be cooked as well as eaten raw. Prepared this way, the stalks taste a little like asparagus.
Some varieties include: Little Gem (a well known semi-cos variety since the late 19th century, but regaining popularity, particularly in Great Britain. It has a firm, sweet heart); Winter Density (another small, sweet-tasting Romain-type lettuce); Bubbles (similar to Little Gem, with crisp crinkly leaves and a good flavour); Lobjoits Green (old variety that is a deep green and crisp); and Valmaine (also good as leaf lettuce).
is becoming popular since its leaves have a more delicate texture and a better flavour than the green-leaf varieties. Their red colour is as a result of anthocyanin, a water soluble pigment and antioxidant, occurring as a metabolic product.
The brightness of the red is also affected to a certain extent by the environment. Lower, or greatly fluctuating temperatures, together with intense light, leads to optimal colouring. Equally, the intensity of the colouring is reduced by low exposure to sunlight and high temperatures over a relatively long period.
Differences in colour between the individual varieties of lettuce, however, are mainly because of the type, and can be controlled by environmental factors only to a limited extent.
Some well-known varieties include Continuity, Four Seasons, and Rougette de Montpellier from France.
Red salad bowl or oakleaf lettuce, feuille de chêne, is grown mainly outdoors and harvested throughout the summer. It is not only tempting because of its attractive leaves, which resemble oak foliage, but also because of its nutty flavour. However, it is highly perishable and if refrigerated, stays fresh for a day at the most.
Chinese Lettuce, Celtuce, Stem Lettuce, Asparagus Lettuce, woh sun (Chinese)
(Lactuca sativa var. augustana – Family Compositae)
The name “celtuce” is a combination of celery and lettuce and given because of its shape, and not because it is a cross between them.
A little known specialty in Europe, it is very closely related to wild lettuce (L. serriola). The stems can be eaten raw or cooked, with the tender young leaves used for salad. This type of lettuce is grown mainly for its thickened fleshy stem which provides an asparagus-like vegetable.
The stems, which can be an inch or two thick, can grow to lengths of four feet. They are then harvested in the summer or early fall. Although it has little nutritional value, this lettuce does make a good addition to any fresh salad; and the Chinese snap it up when it appears in Western markets.
Grown for centuries in China, it is a race of lettuce prized, not necessarily for the leaves, but rather the thick, juicy stems. It is also an ornamental vegetable. Most of China’s crop goes into Shanghai pickles, called “lettuce pickles” in Chinese groceries.
This type of lettuce has been listed in European seed catalogues since 1885, and the name “celtuce” was adopted by an American seed company (Burpee), who first offered the seed in 1942. The seed had been sent to them in 1938 by a missionary in Western China near the Tibetan border.
If planted with chervil and dill, aphids will not be a problem. It also does well planted between such slower-growing crops as cauliflower, self-blanching celery, or Chinese chives. This lettuce is excellent raw and cooked lightly in stir fry. Young leaves can be cooked as greens.
Zulu is a new variety, having narrow dull-textured leaves, that is ideal for cooler climates. Other varieties are sold in seed mixes of broad, dull, glossy, or red leaved types.
Lamb’s Lettuce, corn salad, field lettuce, fetticus, lamb’s tongues, Mâche (French)
(Valerianella locusta or V. olitoria – Family Valerianaceae)
Lamb’s lettuce is an undemanding herb that is widely distributed in Europe and Asia, and has been cultivated only since the beginning of the 20th century. Originating in the temperate zones of Europe, it was first described in 1699 in an English diary.
It was once a common cold-weather salad leaf in the US, and all but disappeared before being resurrected by Americans travelling in Europe. It is now exported from France, the Netherlands, Belgium, and Germany, and, once again, becoming popular with small-scale growers in the US.
Depending on which authority is quoted, the name originated because lambs were partial to it or because it appeared during lambing season. Another name, corn salad, comes from its regular appearance as a cornfield weed.
Mâche is a word seen in specialty groceries and on menus. Chefs prefer to use the French name because, they say, if “corn salad” is used, the clientelle expects just that – a salad made from corn.
It has been popular for centuries in France; but, in England, it declined in popularity in the 1700s, and by the 19th century, declared a noxious weed.
The leaves are a good source of beta carotene, Vitamin C, and folate.
In spite of its delicate appearance, lamb’s lettuce is an extremely hardy plant and particularly valued as a nutritious winter salad crop. The leaves are a bright green and rounded with a slightly nutty taste, and is usually eaten raw as a salad green.
Before the appearance of winter lettuce varieties, lamb’s lettuce was the main winter salad green and at one time, classified in the same genus.
There are two forms: the large or broad-leaved and the darker, more compact, green type which is popular in western Europe, but less productive. It is often planted in the unused damp spaces of gardens or flower beds, and makes the ideal cover between taller crops.
Some varieties include Cavallo, Elan, Jade, Large Leaved, Grote Noordhollandse, Verte de Cambrai, Verte d’Etampes, Vit, and Volhart.