GrassBase - The Online World Grass Flora


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

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

Ischaemum impressum

HABIT Annual; caespitose. Culms 40–60 cm long. Culm-nodes glabrous. Leaf-sheaths 8.5–9 cm long. Ligule an eciliate membrane; 2–2.5 mm long; erose. Leaf-blades lanceolate; 7–10 cm long; 7–15 mm wide. Leaf-blade surface hispid. Leaf-blade margins scabrous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2; paired; appressed back to back; 5 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis internodes clavate; 4.25–4.5 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 clavate; 4–4.25 mm long; 0.9 length of internode; ciliate; hairy on one margin.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate, or oblong; laterally compressed; 5–5.25 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; winged on keels; 9–11 -veined. Companion sterile spikelet lemmas 2; enclosed by glumes; 4–4.6 mm long; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 6.5–6.7 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. Lower glume lanceolate, or oblong; 1 length of spikelet; chartaceous; 2-keeled; keeled all along; keeled laterally; winged on keel; winged narrowly; winged above; 7–9 -veined. Lower glume surface flat; impressed above (convex below); laterally waisted. Lower glume apex dentate; 2 -fid; acuminate; awned; 2 -awned. Upper glume lanceolate; membranous; 1-keeled; winged on keel; 3 -veined. Upper glume surface with a dorsal tuft of hair. Upper glume apex acuminate to setaceously attenuate.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; 4.8–5 mm long; membranous; 3 -veined. Fertile lemma oblong; 4–4.25 mm long; membranous; without keel; 3 -veined. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 17–18 mm long overall; with twisted column. Column of lemma awn glabrous. Palea 4–4.25 mm long.

FLOWER Anthers 3; 1.75–2 mm long.

FRUIT Caryopsis with adherent pericarp; oblong; dorsally compressed; 2–2.25 mm long.

DISTRIBUTION Africa: northeast tropical. Asia-tropical: India.

NOTES Andropogoneae. Patunkar 1993.

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