Porcupine grass

Description

Hesperostipa spartea, formerly Stipa spartea, is a species of grass known by the common names porcupine grass, western porcupine grass, short-awn porcupine grass, porcupine needlegrass, and big needlegrass. It is native to North America, where it is widespread from British Columbia to Ontario in Canada and through the central and Great Lakes regions of the United States. It is a bunchgrass species in the genus Hesperostipa. Hesperostipa spartea is native to the Great Plains and Canadian Prairies of North America. It is also found in grasslands of the Rocky Mountains in Western Canada and the Western United States. This grass is common and is a dominant grass in various prairie and grassland ecosystems in the Great Plains. In Alberta it is codominant with rough fescue on the grasslands. In other areas it may be codominant with little bluestem. It may be a pioneer species or a climax species, occurring in all stages of ecological succession. It thrives on poor soils and it can invade disturbed habitat such as gopher mounds. It can also be a long-term component of climax grassland and prairie. This perennial bunchgrass is similar to needle-and-thread grass, but it has longer, wider, paler leaves. It can reach over a metre in height. The roots are known to reach 1.8 metres (5.9 feet) deep into the soil. The inflorescence is a panicle of spikelets. Each fruit has a very long, twisted awn, reaching up to 19 centimetres (7.5 inches) in length. As the grass expands or contracts according to the temperature and moisture conditions, the awns twist or untwist to eventually drill the seeds into the soil – a phenomenon known as geocarpy. The awns containing several seeds may tangle together and the mass is blown away from the parent plant on the wind. They also stick to animals, another vector of seed dispersal. Hesperostipa spartea has a bunchgrass foliage mass of 3–6 feet (0.91–1.83 m) in diameter. The flower stalks are upright and arching, yellow, in late Spring.