Asparagus is a stem vegetable that grows its spears from the "crown" portion of the plant, which lies beneath the soil. The stalks are rigid, with narrow, leafy heads, yet they are slightly tender in texture, with a noticeable crispness. They vary in color from white to green to purple, with the white variety grown using the process of etiolation. This process deprives the plant of light, which does not allow it to produce chlorophyll (which makes the stalk green). The vegetable has a delicate, slightly bitter flavor with earthy undertones.