Chrysopogon benthamianus

HABIT Perennial; caespitose. Butt sheaths glabrous, or villous; persistent and investing base of culm; with fibrous dead sheaths. Culms erect; 30–120 cm long; 3–5 -noded. Culm-internodes distally glabrous, or pubescent. Culm-nodes glabrous. Lateral branches lacking, or sparse. Leaf-sheaths without keel; glabrous on surface, or pilose; with tubercle-based hairs. Ligule a ciliolate membrane. Leaf-blades 5–45 cm long; 2–4 mm wide. Leaf-blade surface smooth, or scaberulous; glabrous, or pilose; with tubercle-based hairs. Leaf-blade margins scabrous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle with branches tipped by a raceme.

Panicle open; lanceolate; 7–21 cm long. Primary panicle branches whorled at most nodes; 3–6 cm long. Panicle axis glabrous, or pubescent. Panicle branches capillary; flexuous; scaberulous; villous; hairy at tip; pubescent in axils.

Racemes bearing a triad of spikelets; 1 fertile spikelets on each. Rhachis obsolete.

Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels linear; flattened; 3.5–7 mm long; 0.33–0.5 length of fertile spikelet; glabrous, or pubescent; hairy at tip.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; 9–14 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; muticous, or awned; one glume awned. Companion sterile spikelet lemmas enclosed by glumes; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 9–14 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; 1.7–3 mm long; bearded; base acute. Spikelet callus hairs 1–2 mm long.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; cartilaginous; without keels; 5–7 -veined. Lower glume surface scabrous; rough above. Lower glume apex truncate. Upper glume oblong; 1-keeled; 3–5 -veined. Upper glume primary vein pectinately ciliate. Upper glume surface scabrous; rough generally, or above. Upper glume apex obtuse; awned; 1 -awned. Upper glume awn 5–10 mm long.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 5–7.5 mm long; hyaline; 2–3 -veined; ciliolate on margins. Fertile lemma linear; 5.5–7 mm long; hyaline; without keel; 1 -veined. Lemma margins ciliolate. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 20–40 mm long overall; with twisted column. Column of lemma awn scabrous. Palea 3.2–4.2 mm long; 0–2 -veined.

DISTRIBUTION Australasia: Australia.

NOTES Andropogoneae. Fl NSW 1993.

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