Asparagus is the name of a genus of plants, a member of the lily family Asparagaceae. There are over a hundred species, all from the Old World, in both hemisphere and throughout temperate and tropical regions. They range from herbs to somewhat woody climbers.
Asparagus is also used as the name of a vegetable obtained from one species within this genus, specifically the young shoots of Asparagus officinalis. It has been used from very early times as a culinary vegetable, owing to its delicate flavour and diuretic properties.
In its simplest form, the shoots are boiled or steamed until tender and served with a light sauce or melted butter. Small or full-sized stalks can be made into asparagus soup. Cantonese restaurants in the United States often serve asparagus stir-fried with chicken, shrimp, or beef.
One problem with asparagus is that a constituent of the plant is metabolised and excreted in the urine, giving it a distictive, mildly unpleasant odour. The smell was once thought to be methyl mercaptan (methyl sulfide, CH3SH), but it now appears to be some other compound. Everyone excretes the compound, but some (perhaps fortunate) people are genetically incapable of smelling it. The amino acid asparagine gets its name from asparagus, the asparagus plant being rich in this compound.
The shoots of a related plant, Ornithogalum pyrenaicum, called Prussian asparagus, have been used for similar purposes as genuine asparagus.
Other species of asparagus are grown as ornamentals, and are often used for foliage display, and as house plants. Commonly grown ornamental species are Asparagus plumosus and Asparagus sprengerii.