Arundo donax

HABIT Perennial. Rhizomes short (internodes less than 2cm long). Culms erect; reed-like; 200–600 cm long. Culm-internodes hollow. Culm-nodes glabrous. Leaves cauline. Leaf-sheaths glabrous on surface. Ligule a ciliolate membrane. Leaf-blades drooping; 20–80 cm long; 10–70 mm wide. Leaf-blade surface smooth; glabrous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; oblong; 30–60 cm long. Primary panicle branches profusely divided. Panicle branches scaberulous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 3–5 fertile florets; with a barren rhachilla extension. Spikelets cuneate; laterally compressed; 8–15 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; pilose; hairy on the surface; obtuse.

GLUMES Glumes persistent; similar; reaching apex of florets; similar to fertile lemma in texture. Lower glume lanceolate; 1 length of upper glume; membranous; 1-keeled; 3–5 -veined. Lower glume surface glabrous. Lower glume apex acute. Upper glume lanceolate; 1.25 length of adjacent fertile lemma; membranous; 1-keeled; 3–5 -veined. Upper glume surface glabrous. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; 6–12 mm long; membranous; without keel; 5–9 -veined. Lemma surface villous; hairy below. Lemma hairs 5–8 mm long. Lemma apex acute, or acuminate; muticous, or mucronate. Palea 0.5–0.7 length of lemma; 2 -veined. Palea keels ciliolate.

FLOWER Lodicules 2. Anthers 3; 2.5–3 mm long. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; ovoid; 2 mm long. Embryo 1 length of caryopsis. Hilum punctiform.

DISTRIBUTION Europe: southwestern, southeastern, and eastern. Africa: north, Macaronesia, northeast tropical, south, middle Atlantic ocean, and western Indian ocean. Asia-temperate: Soviet Middle Asia, Caucasus, western Asia, Arabia, China, and eastern Asia. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia and New Zealand. Pacific: southwestern, south-central, northwestern, and north-central. North America: southwest USA, south-central USA, southeast USA, and Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, Brazil, and southern South America.

NOTES Arundineae. FTA.

ADDITIONAL CHARACTERS Callus hairs oblique.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.