The harebell family contains mostly perennial plants, although some are annual or biennial, but hardly any shrubs. Plants of this family are found in most parts of the world except Africa, although the majority are found in the temperate regions. There are about about 70 genera and 2000 species worldwide.
The flowers are most usually blue. It is the flowers which give this plant family its name. Campanula is Latin for bell, and the majority of the flowers are bell-shaped to some degree. They may be long tubular bells, or open starry shapes. The flower parts are in fives - this is most noticeable in the five points at the end of the bell, and the five points to the sepals (calyx). Flowers occur in all shades of blue, and in mauves, purples, white, and rarely pink or cream.
There is a variety of leaf shapes in this family, although they are undivided. They may be kidney-shaped, oval, round, or like a nettle. The stem varies with the size and type of the plant - it may be woody, wiry or brittle. The root is often a tuber or at least fleshy.
Each single flower can produce thousands of seeds. They usually form in three chambers in the seed capsule, and are usually tiny.
Pretty flowers are not the only potential benefit from this group. Many species produce chemical compounds in wide variety. Some of these compounds are highly toxic, but others have been used to treat asthma and other breathing disorders. Perhaps the best known compound is lobeline, a mild narcotic which provides the slight rush and calming effect of nicotine, but which does not appear to be addictive. As such, it can be used as an aid to quit smoking, though its sale is now regulated in some countries.