Plants perennial; rhizomatous, rhizomes short, usually more than 1 cm thick. Culms 2-10 m tall, 1-3.5 cm thick, usually erect, occasionally pendant from cliffs; nodes glabrous; internodes hollow. Leaves cauline, conspicuously distichous, glabrous; sheaths open, longer than the internodes; ligules membranous, shortly ciliate; blades flat or folded, margins scabrous. Panicles terminal, plumose, silvery to purplish. Spikelets laterally compressed, with 1-several florets; rachilla internodes glabrous; disarticulation above the glumes and between the florets. Glumes longer than the florets, 3-5-veined; lemmaspilose, hairs not papillose-based, 3-7-veined, apices entire or minutely awned; paleas shorter than the lemmas, 2-veined; anthers 3. x = 12. Name from the Latin arundo, reed.

Arundo, a genus of three species, grows throughout the tropical and warm-temperate regions of the world. Only one species has been introduced to the Western Hemisphere.

Arundo is similar to, but usually larger than, Phragmites, a much more common genus in North America. In addition, Arundo, but not Phragmites, has a wedge-shaped, light to dark brown area at the base of its blades.

1.   Arundo donax L.
Giant Reed

Culms (2)3-10 m, in large tussocks or hedges. Leaves distichous; ligules 0.4-1 mm; blades 30-100 cm long, 2-7(9) cm wide, with a wedge-shaped, light to dark brown area at the base. Panicles 30-60 cm long, to 30 cm wide. Spikelets 10-15 mm, with 2-4 florets. Glumes subequal, as long as the spikelets, thin, brownish or purplish, 3-veined, long-acuminate; lemmas 8-12 mm, 3-5-veined, pilose, hairs 4-9 mm, apices bifid, midvein ending into a delicate awn; paleas 3-5 mm, pilose at the base; anthers 2-3 mm. Caryopses 3-4 mm, oblong, light brown. 2n = 24, 100, 110.

Within the Flora region, Arundo donax grows in the southern half of the contiguous United States, being found along ditches, culverts, and roadsides where water accumulates. It has been used extensively as a windbreak, and planted for erosion control on wet dunes. It is also grown for the ornamental value of its tall, leafy culms and large panicles, but its tendency to spread is sometimes a disadvantage. Cultivars with striped or unusually wide leaves, e.g., 'Variegata' and 'Macrophylla', are of horticultural interest but do not merit taxonomic recognition.

Arundo donax has been used for thousands of years in making musical instruments, the stems being used for pipes and the tough inner rind for reeds in a wide variety of woodwind instruments. It is one of the species referred to as reed in the Bible. It is still used in many parts of the world for house construction, lattice-work, mats, screens, stakes, walking sticks, and fishing poles.