Monday, February 15, 2010

Vegetable Profile: Lettuce

By Nina Berryman

The common lettuce, so popular and loved! Lactuca sativa is in the Asteraceae family, as are sunflowers, dandelions, and the artichoke. All of these plants may seem quite different from one another at first, but one characteristic proves their genetic similarity- their flowers. Plants in the Asteraceae family all have flower heads that are actually made up of many, many tiny flowers. Take the dandelion for instance, each little yellow (what is commonly mistook for) petal, is actually an individual flower. The tiny parts in the disc of a sunflower are actually individual flowers as well.

The lettuce flower is no exception, and has flowers similar to other members in the Asteraceae family. These days, it is not uncommon to see lettuce bolting and going to seed. Bolting is the process when a plant puts energy into flower production instead of leaf production. As a result the leaves get smaller, the stem gets taller and flowers start to form. Generally the whole taste of a plant will change, and in the case of lettuce, the leaves will taste much more bitter. Lettuce bolts in response to the length of day. The lettuce flower is a rare sight, as most gardeners can recognize the lengthening of the stalk as a bad sign and harvest it right away. If you let the lettuce keep growing though, you’ll see small flower heads forming, each containing many individual flowers. Each flower, or floret, produces one seed. All the florets in one head open on the same day. They are open only briefly, long enough to pollinate themselves, then close and never reopen. After the seeds develop and the flower head starts the dry, the similarity between lettuce and dandelions will again become apparent. The seeds will blow away in the wind, carried by fluffy chaff.

Source: Seed to Seed, by Suzanne Ashworth

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