Diverse genus with approximately 185 herbaceous, tuberous species in the flowering plant, Orchidaceae family of orchids. Most species are terrestrial and grow in or on the soil, some are epiphytic and able to grow without the need for soil substrate, instead gleaning nutrition from their immediate surroundings. Some are lithophytes, these plants grow without soil in or on rocks. Most species are indigenous to tropical and Southern Africa, Madagascar, Réunion and the Arabian Peninsula. Capable of growing to a maximum height of around 1m in height, these plants produce beautiful flowers in a wide range of colours including red, green, brown, orange, yellow, white, blue, purple and pink. Flowers are produced in clusters on raceme or corymb structures and their top petals are fused into a hooded structure, with two free petals at the base. Flowers often have attractive venation or speckled patterning on the inner petal surfaces.