Sorghum stipoideum

HABIT Annual. Culms 100–300 cm long; 7–13 mm diam.; 3–6 -noded; without nodal roots, or with prop roots. Culm-internodes distally pruinose. Culm-nodes glabrous, or pubescent, or bearded. Lateral branches sparse. Ligule an eciliate membrane; 0.7–3.7 mm long. Leaf-blades 5–70 mm wide.

INFLORESCENCE Inflorescence a panicle with branches tipped by a raceme.

Panicle open; dense; 14–38 cm long; 2–3 cm wide. Primary panicle branches 1–14 -nate; sparsely divided; 6–10 cm long. Panicle branches angular, or flat; scabrous; pubescent in axils, or bearded in axils.

Racemes 1.5–3.2 cm long; bearing a triad of spikelets, or few fertile spikelets; bearing 1(–3) fertile spikelets on each. Rhachis evident, or obsolete; fragile at the nodes; ciliate on margins. Rhachis internodes linear. Rhachis internode tip oblique.

Spikelets in pairs, or in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster, or 2 in the cluster. Pedicels filiform; flattened; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 8–18 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; 7–9 -veined; glabrous to pilose; ciliate on margins; entire, or dentate; 2 -fid; muticous, or mucronate, or awned; one glume awned; with 0–2.3 mm long awn. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets linear, or elliptic; dorsally compressed; 17–18 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; curved; 3.3–8.5 mm long; base pungent.

GLUMES Glumes dissimilar; with lower wider than upper; exceeding apex of florets; firmer than fertile lemma; dull, or shiny. Lower glume ovate; 1 length of spikelet; coriaceous; much thinner above; without keels; keel-less except near apex; 8–11 -veined. Lower glume surface glabrous to pilose. Lower glume apex acute. Upper glume ovate; coriaceous; much thinner above; without keels; 7 -veined. Upper glume surface glabrous to pilose. Upper glume margins eciliate, or ciliate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; hyaline; 2 -veined; acute. Fertile lemma oblong; hyaline; 1 -veined. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 80–155 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

FLOWER Lodicules 2; oblong; 0.5–1 mm long; fleshy; glabrous, or ciliate. Anthers 3; 4.2–6 mm long. Stigmas 2. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; oblong; dorsally compressed; 2.5–5 mm long; apex umbonate.

DISTRIBUTION Australasia: Australia.

NOTES Andropogoneae. Lazarides 1993.

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