The grass family Poaceae contains approximately 675 genera, including Stipa, which contains 300 separate species from temperate and warm-temperate regions. All species of Stipa have linear, pleated leaves and have panicles of flat spikelets. Stipa gigantea, or giant oat, is one of the most admired species, originating from Spain and north west Africa, where it grows in stony, scrub-covered hillsides. It produces dense clumps of slender foliage, from which emerge long stems to 2.5m in height. These develop slender panicles of oat-like heads in summer, which take on golden hues in autumn. It is at this time of year that they really come into their own, when the swaying stems and panicles are lit up in the sun.