Oats are annual plants and often reach 1.5 metres (5 feet) in height. The long leaves have rounded sheaths at the base and a membranous ligule (small appendage where the leaf joins the stem). The flowering and fruiting structure, or inflorescence, of the plant is made up of numerous branches bearing florets that produce the caryopsis, or one-seeded fruit. Common oats are grown in cool temperate regions; red oats, more heat tolerant, are grown mainly in warmer climates. With sufficient moisture, the crop will grow on soils that are sandy, low in fertility, or highly acidic. The plants are relatively free from diseases and pests, though they are susceptible to rust and anthracnose on their stems and leaves. Rolled oats, flattened kernels with the hulls removed, are used mostly for oatmeal; other breakfast foods are made from the groats, which are unflattened kernels with husks removed. Oat flour is not generally considered suitable for bread but is used to make cookies and puddings. The grains are high in carbohydrates and contain about 13 percent protein and 7.5 percent fat. They are a source of calcium, iron, vitamin B1, and niacin. As a livestock feed, the grain is used both in pure form and in mixtures, though the demand for oats has been somewhat reduced by competition from hybrid corn (maize) and alfalfa. The straw is used for animal feed and bedding. In industry oat hulls are a source of furfural, a chemical used in various types of solvents.