Common name

Plume Sorghum
Perennial Sorghum
Perennial Canegrass

Derivation
Sarga Ewart, Proc. Roy. Soc. Victoria ser. 2, 23: 296 (1911) meaning obscure, origin not given by author but possibly alluding to being intermediate between Agrostis and Stipa.

plumosum- Latin for feathery. With long hairs giving the pedicels a feathery appearance.

Published in
Austral. Syst. Bot. in press.

Common synonyms

Sorghum grande Lazarides
Sorghum interjectum Lazarides
Sorghum plumosum (R.Br.) P.Beauv.
Sorghum plumosum (R.Br.) P.Beauv. var. teretifolium Lazarides

Habit
Perennial, tufted, short-lived. Rhizomes short. Basal leaf sheaths glabrous or pubescent or pilose. Culms erect, robust, 100–300 cm tall, 3–7 mm diam., 4–7-noded, without nodal roots or with aerial roots from the nodes. Mid-culm internodes pruinose or glabrous. Mid-culm nodes glabrous or pubescent or bearded. Lateral branches simple or sparsely branched. Leaf-sheaths hirsute, with simple or tubercle-based hairs. Ligule a fringed membrane, 1.5–3.7 mm long. Leaf-blades flat or conduplicate or terete, 15–40 cm long, 4–16 mm wide. Leaf-blade surface puberulous to hirsute. Leaf-blade apex filiform.

Inflorescence
Panicle open or contracted, linear or lanceolate, dense, 12.5–45 cm long, 2–5 cm wide. Primary panicle branches 1–8 -nate, simple or sparsely divided or moderately divided, 3–7 cm long. Panicle branches terete or angular or flat, smooth or scaberulous or scabrous, rough distally, glabrous or villous, glabrous or pubescent or bearded in axils, with prominent pulvini. Rames 2–3.5 cm long, bearing 1–6 fertile spikelets on each. Rhachis ciliate on margins. Rame internodes filiform or linear, 4–5 mm long. Rame internode tip transverse or oblique.

Spikelets
Spikelets in pairs, one sessile and fertile and the other (companion) spikelet pedicelled. Pedicels filiform, flattened, 4.5–7 mm long, ciliate. Companion spikelets developed, containing empty lemmas or male, linear or lanceolate, dorsally compressed, 7–13 mm long, shorter than fertile or as long as fertile, persistent or separately deciduous. Companion spikelet glumes chartaceous, 3–7-nerved, pubescent or pilose or villous, ciliate on margins, acuminate, muticous. Companion spikelet lemmas enclosed by glumes. Fertile spikelets 2-flowered, comprising 1 fertile floret, lower floret sterile, upper fertile, without rhachilla extension, elliptic, dorsally compressed, 6–18 mm long, falling entire, deciduous with accessory branch structures. Spikelet callus cuneate, curved, 0.5–10 mm long, base obtuse or acute or pungent.

Glumes
Glumes dissimilar, with lower wider than upper. Lower glume ovate, 100% of length of spikelet, cartilaginous or coriaceous, much thinner above, keel-less except near apex, 5–9-nerved. Lower glume lateral nerves without connecting nerves or with cross-nerves. Lower glume surface pubescent or pilose or hirsute or villous, with simple r tubercle-based hairs. Lower glume apex acute. Upper glume ovate, cartilaginous or coriaceous, much thinner above, 5–9-nerved. Upper glume lateral nerves with or without cross-nerves. Upper glume surface pubescent or pilose or hirsute or villous.

Florets
Basal sterile floret 1, without significant palea. Lemma of lower sterile floret lanceolate or elliptic, 80% of length of spikelet, hyaline, 2-nerved, acute. Fertile lemma oblong, 2–3 mm long, hyaline, 1-nerved. Lemma margins ciliate. Lemma apex dentate or lobed, 2-fid, 1-awned. Median (principal) awn geniculate, 25–100 mm long overall, with a twisted column. Column glabrous or pubescent or ciliate, hairy on the spiral. Palea absent or minute. Lodicules 2, oblong, 0.6–1 mm long, fleshy, ciliate, hairy across the apex or on the corners. Anthers 3, 3.6–4.2 mm long. Stigmas 2. Ovary glabrous. Grain with adherent pericarp, obovoid, 3.3–4.5 mm long, glabrous, truncate.

Continental Distribution:
Australasia.

Australian Distribution:
Northern Territory, Queensland.

Northern Territory: Darwin & Gulf. Queensland: Cook, Burke, North Kennedy, South Kennedy, Port Curtis, Leichhardt, Wide Bay, Gregory North, Mitchell, Warrego.

Classification. (GPWG 2001):
Panicoideae: Andropogoneae

Notes
Native.