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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 guianense
HABIT Perennial; caespitose. Culms 50–170 cm long. Culm-internodes distally glabrous. Leaf-sheaths glabrous on surface, or hispid; with tubercle-based hairs. Ligule a ciliolate membrane; 1.3–2 mm long. Leaf-blades 15–25 cm long; 8–20 mm wide. Leaf-blade surface glabrous, or pubescent.
INFLORESCENCE Inflorescence composed of racemes.
Racemes 2–5(–9); digitate; 4–8.5 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. 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 oblong; 2.5–3 mm long; 0.33–0.5 length of fertile spikelet; ciliate.
STERILE SPIKELETS Companion sterile spikelets well-developed; male; oblong; 4.5–8 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; muticous. Companion sterile spikelet lemmas 1-awned.
FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 4.5–8 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; pubescent; base truncate; inserted.
GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; much thinner above; 2-keeled; keeled above; keeled laterally; 7 -veined. Lower glume surface convex; scabrous. Lower glume apex dentate; 2 -fid. Upper glume lanceolate; coriaceous; 1-keeled; keeled above; 5 -veined. Upper glume primary vein scabrous. Upper glume mucronate, or awned; 1 -awned. Upper glume awn 0.5 mm long.
FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; 4–5 mm long; membranous. Fertile lemma oblong; 3.5–4.5 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; 7–10 mm long overall; with twisted column. Column of lemma awn 1–2 mm long; glabrous.
FLOWER Anthers 3.
DISTRIBUTION South America: northern South America and Brazil.
NOTES Andropogoneae. Fl Guian 1994.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
