Chrysopogon rigidus

Chrysopogon rigidus (B.K. Simon) Veldkamp. Austrobaileya 5: 527 (1999).

Classification. (GPWG 2001) : Subfamily Panicoideae. Andropogoneae.

Basionym and/or Replacement Name:  Vetiveria rigida B.K. Simon, Austrobaileya 3(1): 95, f. 10 (1989).

Type of Basionym or Protologue Information: Australia: Queensland: Watson River Crossing on Merluna-Arukun road, Cape York Peninsula, 29 May 1982, J.R. Clarkson 4419 (HT: BRI; IT: CANB, K, MBA, NSW, QRS).

Recent synonyms: Vetiveria rigida.

Key references (books and floras): [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of Australia.

Habit. Perennial. Culms erect, 130–150 cm tall, 3–4 -noded. Lateral branches branched. Ligule a fringe of hairs. Leaf-blades 30–50 cm long, 3–5 mm wide.

Inflorescence. Inflorescence compound, a panicle of rames. Panicle lanceolate, 20–27 cm long, 8–10 cm wide. Rhachis fragile at the nodes.

Spikelets. Spikelets sessile, 1 in the cluster. Companion spikelets pedicelled, 1 in the cluster. Companion spikelets developed, containing empty lemmas, 4–5 mm long. Companion spikelet glumes muticous. Fertile spikelets 2-flowered, the lower floret barren (rarely male), the upper fertile, comprising 1 basal sterile florets, comprising 1 fertile floret(s), without rachilla extension, linear or lanceolate, laterally compressed, 6–9 mm long.

Glumes. Glumes dissimilar, firmer than fertile lemma. Lower glume lanceolate, cartilaginous, without keels, 3 -nerved. Upper glume lanceolate, cartilaginous, keeled, 1-keeled, 3 -nerved. Upper glume apex awned. Florets. Basal sterile florets 1, barren, without significant palea. Lemma of lower sterile floret hyaline, 2 -nerved.

Fertile lemma 2 mm long, without keel. Lemma apex dentate, awned, 1 -awned. Median (principal) awn from a sinus, 8–10 mm long overall. Palea 0 -nerved, without keels. Anthers 3. Grain 3–5 mm long.

Continental Distribution: Australasia.

Australian Distribution: Queensland.

Queensland: Cook.

Notes. Found in the same habitats as C. filipes but only in northern Qld. Flowers Apr.--May.

AVH 2011

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith