Clausospicula extensa M. Lazarides. Austral. Syst. Bot. 4: 399 (1991).
Classification. (GPWG 2001) : Subfamily Panicoideae. Andropogoneae.
Type of Basionym or Protologue Information: Australia: Northern Territory: Darwin and Gulf Distr.: South Alligator River, c. 26 km WSW of Mt. Evelyn, 13.40S 132.40E, 26 Feb 1973, Adams & Lazarides 3113 (HT: CANB; IT: CANB).
Key references (books and floras):  D.Sharp & B.K.Simon, AusGrass, Grasses of Australia.
Habit. Annual. Culms 30–45 cm tall, 5–7 -noded. Mid-culm nodes glabrous. Lateral branches sparsely branched. Leaf-sheaths hairy. Ligule a fringed membrane, a ciliolate membrane, 0.3–0.5 mm long. Leaf-blades flat or conduplicate, 30 cm long, 1.4–2.6 mm wide. Leaf-blade surface indumented.
Inflorescence. Inflorescence compound, a panicle of rames. Panicle 20 cm long, 8 cm wide. Rhachis obsolete.
Spikelets. Spikelets sessile, 1 in the cluster. Companion spikelets pedicelled, 2 in the cluster. Companion spikelets absent or rudimentary, comprising 2 subequal glumes without lemmas, 5–12 mm long. 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, obovate, dorsally compressed, 10 mm long.
Glumes. Glumes dissimilar, firmer than fertile lemma, shiny. Lower glume obovate, coriaceous, much thinner above, without keels. Lower glume apex muticous or mucronate or awned. Upper glume lanceolate or oblong, coriaceous. Upper glume apex awned. Florets. Basal sterile florets 1, barren, without significant palea. Lemma of lower sterile floret hyaline, 2 -nerved.
Fertile lemma 3 -nerved. Lemma apex awned, 1 -awned. Median (principal) awn apical, 85–105 mm long overall, with a twisted column. Column 40–55 mm long. Palea absent. Lodicules present. Anthers 3. Grain 5.6 mm long.
Continental Distribution: Australasia.
Australian Distribution: Northern Territory.
Northern Territory: Darwin & Gulf.
Notes. Endemic to the western Arnhemland region of N.T. Flowers Feb.--May.