GrassBase - The Online World Grass Flora

Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Panicum jacobsianum

HABIT Perennial; caespitose. Culms erect; 10–20 cm long. Culm-internodes hollow; distally glabrous. Culm-nodes glabrous. Lateral branches sparse. Leaf-sheaths longer than adjacent culm internode; without keel; glabrous on surface; outer margin glabrous. Ligule an eciliate membrane; 1.5–2.8 mm long; entire, or erose; truncate, or obtuse. Collar glabrous. Leaf-blades involute; 4–10 cm long; 1.6–2.5 mm wide. Leaf-blade surface scaberulous; pilose; hairy adaxially. Leaf-blade margins scaberulous. Leaf-blade apex acuminate; hardened.

INFLORESCENCE Inflorescence a panicle.

Panicle open; oblong; 4–8 cm long. Primary panicle branches whorled at lower nodes; bearing 1–3 fertile spikelets on each lower branch. Panicle axis 4–8 noded; scabrous. Panicle branches pubescent in axils.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels angular; 15–20 mm long; scabrous; tip cupuliform.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; 2.5–2.9 mm long; 1.1–1.3 mm wide; falling entire. Rhachilla internodes elongated between glumes.

GLUMES Glumes reaching apex of florets; thinner than fertile lemma. Lower glume ovate; clasping; 1.7–2.1 mm long; 0.6–0.7 length of spikelet; membranous; without keels; 5–7 -veined. Lower glume surface scabrous. Lower glume apex acute, or acuminate. Upper glume elliptic; 2.2–2.6 mm long; 1 length of spikelet; membranous; without keels; 7–9 -veined. Upper glume surface pilose. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret similar to upper glume; elliptic; 2.2–2.6 mm long; 1 length of spikelet; chartaceous; 7–9 -veined; with equidistant veins. Fertile lemma elliptic; dorsally compressed; 1.7–2.1 mm long; indurate; pallid; without keel. Lemma margins involute. Lemma apex acute. Palea involute; indurate.

DISTRIBUTION Australasia: Australia.

NOTES Paniceae. Whalley & Bruhl 2011.

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