Cymbopogon ambiguus

HABIT Perennial; caespitose. Butt sheaths pubescent. Basal innovations extravaginal. Culms erect; 55–60 cm long. Culm-internodes distally glabrous, or pubescent. Leaf-sheaths glabrous on surface. Leaf-sheath auricles absent, or erect. Ligule an eciliate membrane; 1.9–9 mm long; membranous. Leaf-blades filiform, or linear; 20–35 cm long; 1–2 mm wide; aromatic. Leaf-blade surface scabrous; glabrous. Leaf-blade apex attenuate.

INFLORESCENCE Synflorescence compound; linear, or paniculate; 10–20 cm long; dense. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed. Spatheole elliptic; 4–9 cm long; chartaceous; glabrous.

Racemes 2; paired; erect; 1.5–2 cm long. Rhachis fragile at the nodes; semiterete; villous on surface. Rhachis internodes linear. Rhachis internode tip transverse; cupuliform. Raceme-bases flattened; subequal.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; semiterete; villous.

STERILE SPIKELETS Basal sterile spikelets absent.

Companion sterile spikelets well-developed; comprising 2 subequal glumes without lemmas; linear; 3–4 mm long; shorter than fertile; deciduous with the fertile. Companion sterile spikelet glumes chartaceous; 7 -veined; glabrous; acute; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or ovate; dorsally compressed; 5.5–6.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus base obtuse; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate, or ovate; 1 length of spikelet; chartaceous; 2-keeled; keeled all along; keeled laterally; winged on keel; winged narrowly. Lower glume intercarinal veins distinct; 3–4 in number. Lower glume surface flat, or concave; impressed below. Lower glume apex acuminate. Upper glume lanceolate; 1-keeled. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret hyaline. Fertile lemma lanceolate; hyaline; without keel. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 15 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

FLOWER Anthers 3.

FRUIT Caryopsis with adherent pericarp; oblanceolate; isodiametric; 2 mm long.

DISTRIBUTION Australasia: Australia.

NOTES Andropogoneae. Soenarko 1993.

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