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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.
Ischaemum aureum
HABIT Perennial; caespitose. Culms erect; 25–45 cm long. Leaves cauline. Ligule an eciliate membrane; 0.8–1 mm long. Leaf-blades 3–12 cm long; 3–8 mm wide. Leaf-blade apex acuminate.
INFLORESCENCE Inflorescence composed of racemes.
Racemes 2; paired; 2–5 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis hairs yellow; 3–5 mm long. Rhachis internodes oblong; 2.5–3 mm long; flat and forming a U or V shape with the pedicel in rear view. Rhachis internode tip transverse; cupuliform.
Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels cuneate; angular; ciliate.
STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 4–4.5 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; awned; both glumes awned; with 1.5–2 mm long awn. Companion sterile spikelet lemmas 2; enclosed by glumes; 1-awned (geniculately); with 15–18 mm long awn.
FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4–5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pilose; base obtuse; inserted.
GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate, or ovate; 1 length of spikelet; chartaceous; 2-keeled; keeled laterally; wingless. Lower glume primary vein ciliate (yellow hairs). Lower glume surface flat. Lower glume apex dentate; 2 -fid. Upper glume lanceolate; chartaceous; 1-keeled. Upper glume surface pilose; hairy above. Upper glume apex dentate; 2 -fid; awned; 1 -awned. Upper glume awn 2–3 mm long.
FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; 1 length of spikelet; hyaline. Fertile lemma oblong; 3–4 mm long; membranous; without keel. Lemma apex lobed; 2 -fid; incised 0.33–0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 15–25 mm long overall; with twisted column. Column of lemma awn glabrous. Palea 1 length of lemma.
DISTRIBUTION Asia-temperate: eastern Asia.
NOTES Andropogoneae. Koyama.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
