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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 longisetum
HABIT Perennial; caespitose. Culms 30–50 cm long; 1–1.5 mm diam. Lateral branches lacking. Ligule an eciliate membrane; 1 mm long. Leaf-blades linear, or lanceolate; 8–12 cm long; 7–12 mm wide. Leaf-blade surface glabrous. Leaf-blade apex acuminate.
INFLORESCENCE Inflorescence composed of racemes.
Racemes 2; paired; 6–10 cm long. Rhachis fragile at the nodes; angular; villous on surface; ciliate on margins. Rhachis hairs tawny; 2–4 mm long. Rhachis internodes oblong; 3–4 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 oblong; 3–4 mm long; 1 length of internode; villous; with tawny hairs; with 3–4 mm long hairs.
STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas; lanceolate; laterally compressed; 6 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled. Companion sterile spikelet lemmas 1-awned; with 17–20 mm long awn.
FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; 7–9 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pilose; base truncate; inserted.
GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma; shiny. Lower glume lanceolate; coriaceous; 2-keeled; keeled above; keeled laterally; winged on keel; winged narrowly; winged above. Lower glume surface glabrous. Lower glume margins ciliate. Lower glume apex dentate; 2 -fid. Upper glume lanceolate; coriaceous; 1-keeled; keeled above. Upper glume apex acuminate.
FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; 5 mm long; hyaline. Fertile lemma oblong; 5 mm long; membranous; without keel. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 30–35 mm long overall; with twisted column. Column of lemma awn glabrous. Palea 1 length of lemma.
FLOWER Anthers 3; 2–2.5 mm long.
DISTRIBUTION Pacific: northwestern.
NOTES Andropogoneae. Merrill 1993.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
