Sorghum arundinaceum* (Desv.) Stapf. Fl.
Trop. Afr. 9: 116 (1917).
Classification. (GPWG 2001) : Subfamily
Panicoideae. Andropogoneae.
Basionym and/or
Replacement Name: Rhaphis
arundinacea Desv., Mem. Soc. Agric. Angers 1: 173 (1831);
Andropogon arundinaceus Willd. Sp. Pl. 4: 906 (1806), non Bergius
(1767).
Type of Basionym or
Protologue Information: HT: Isert s.n., Ghana (B-W-18639).
Recent synonyms:
S. bicolor subsp. arundinaceum, S. verticilliflorum.
Key references
(books and floras): [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of
Australia.
Habit. Annual
or perennial. Rhizomes absent. Culms erect, 30–400 cm tall, 2–15 mm diam.
Mid-culm internodes hollow, thin-walled. Mid-culm nodes glabrous or pubescent.
Lateral branches simple. Leaves cauline. Leaf-sheaths smooth, glabrous on
surface. Ligule a fringed membrane, a ciliolate membrane or a ciliate membrane,
2–3 mm long, abaxially glabrous, entire, truncate. Leaf-blades 5–85 cm long,
5–70 mm wide. Leaf-blade surface smooth.
Inflorescence.
Inflorescence compound, a panicle of rames. Panicle linear or lanceolate or
ovate, 10–60 cm long. Rhachis fragile at the nodes.
Spikelets.
Spikelets sessile, 1 in the cluster. Companion spikelets pedicelled, 1 in the
cluster. Companion spikelets represented by single glumes or developed,
comprising 2 subequal glumes without lemmas or male, 3–8 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, lanceolate to
ovate, dorsally compressed, 4–9 mm long.
Glumes. Glumes
dissimilar, firmer than fertile lemma, shiny. Lower glume ovate, coriaceous,
much thinner above, without keels, 9–13 -nerved. Lower glume surface
indumented. Upper glume ovate, coriaceous, without keels, 7–8 -nerved. Upper
glume surface indumented. Florets. Basal sterile florets 1, barren,
without significant palea. Lemma of lower sterile floret 80 % of length of
spikelet, hyaline, 2 -nerved.
Fertile lemma 1–5 mm
long, 1 -nerved. Lemma apex dentate, muticous or awned, 1 -awned. Median
(principal) awn from a sinus, 0–30 mm long overall, with a twisted column.
Palea absent. Lodicules present. Anthers 3. Grain 2–3.5 mm long.
Continental
Distribution: Africa, Temperate Asia, Tropical Asia, Australasia, Pacific,
North America, and South America.
Australian Distribution:
Queensland, Norfolk I.
Queensland:
Burke, Burnett, Cook, Darling Downs, Leichhardt, Moreton, North Kennedy, Port
Curtis, South Kennedy, Wide Bay.
Notes. Widespread weed in the
coastal areas of Qld and northern N.S.W. Flowers Mar.--May.
