Growing in dense tufts, the desert grass (Stipagrostis plumosa) has many erect culms (the hollow, jointed stem of a grass or sedge), encased in woolly sheaths. The ligules between the leaf blade and the sheath have a fringe of hairs, and the leaf blades are curled, coming to sharp point at the tip (2)(3). The inflorescence of the desert grass is a specialised, leafless branch system, borne along the main stem. The flowers are known as ‘spikelets’ and are greatly reduced, surrounded by two scale-like bracts(4).
The desert grass generally flowers between February and July (7). The spikelets have both male and female reproductive structures, and the florets (the small, reduced flowers) open for just a few hours when mature to allow wind pollination(4). The desert grass has specialised roots enclosed in a ‘rhizosheath’, where the root hairs and sand grains form a casing around the roots which is held together by a sticky, glue-like mucilage. The rhizosheath structure allows the desert grass to absorb water much more efficiently from the surrounding environment, and also promotes the growth of nitrogen-fixing bacteria, which produce nitrogen compounds that can be used by the plant (9). The desert grass plays an important ecological role in arid environments by stabilising the sandy substrates through the accumulation of drifting sand around the tussocks (6)(9).
There are no known threats to the desert grass; however, throughout the United Arab Emirates large plots of land have been developed to cater for the rapidly expanding human population, with significant negative impacts on much of the native vegetation (9).
The reproductive shoot of a plant, which bears a group or cluster of flowers.
In grasses and sedges, an outgrowth from the inner junction of a grass leaf sheath and blade, often membranous, sometimes a fringe of hairs. In other plants, may refer to any strap-like appendage.
The transfer of pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.
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