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 nativitatis

HABIT Perennial. Culms erect; 40–60 cm long. Culm-nodes glabrous. Ligule an eciliate membrane. Leaf-blades 6–10 cm long; 4–5 mm wide. Leaf-blade surface glabrous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2; paired; appressed back to back; 4–5 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis hairs yellow. Rhachis internodes oblong; 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; ciliate; with yellow hairs.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; elliptic; laterally compressed; 3–4 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; awned; one glume awned; with 2–4 mm long awn. Companion sterile spikelet lemmas 2; enclosed by glumes; 1-awned; with 6–8 mm long awn.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 4–5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pubescent; base truncate; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; 2-keeled; keeled above; keeled laterally; winged on keel; winged above. Lower glume surface flat. Lower glume apex dentate; 2 -fid. Upper glume ovate; 1 length of spikelet; coriaceous; 1-keeled. Upper glume apex acuminate; awned; 1 -awned. Upper glume awn 6–8 mm long.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; hyaline. Fertile lemma lanceolate; hyaline; without keel. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 14–16 mm long overall; with twisted column. Column of lemma awn glabrous.

FLOWER Anthers 3.

DISTRIBUTION Asia-tropical: Malesia.

NOTES Andropogoneae. Renvoize 1997.

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