Andropogon tsaratananensis

HABIT Perennial; caespitose. Culms erect; 40–60 cm long. Culm-internodes smooth; distally glabrous. Lateral branches ample. Leaves mostly basal. Leaf-sheaths keeled; striately veined; glabrous on surface. Leaf-sheath oral hairs scanty, or lacking. Ligule a ciliolate membrane; 1–2 mm long; membranous; truncate. Leaf-blades erect; straight, or curved; flat; 7–21 cm long; 1.5–3.5 mm wide; stiff; mid-green. Leaf-blade surface smooth, or scaberulous; rough abaxially; glabrous; hairless throughout. Leaf-blade margins scaberulous. Leaf-blade apex acute, or attenuate.

INFLORESCENCE Synflorescence simple. Inflorescence composed of racemes.

Racemes 2; paired; 4.5–7 cm long. Rhachis fragile at the nodes; ciliate on margins. Rhachis hairs 1–2.5 mm long. Rhachis internodes cuneate; 3–5 mm long. Rhachis internode tip transverse; cupuliform; with simple rim.

Spikelets appressed; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels clavate; ciliate; with 1–2.5 mm long hairs.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; dorsally compressed; 4–6 mm long; shorter than fertile. Companion sterile spikelet glumes chartaceous; scabrous; acute; awned; one glume awned; with 1–2.5 mm long awn. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 5–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus square; 1 mm long; pilose; base obtuse; inserted. Spikelet callus hairs 1.5 mm long.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 5–7 mm long; 1 length of spikelet; coriaceous; 2-keeled; keeled dorsally. Lower glume primary vein scaberulous. Lower glume surface concave. Lower glume margins ciliolate. Lower glume apex dentate; 2 -fid. Upper glume lanceolate; chartaceous; 1-keeled. Upper glume primary vein ciliolate. Upper glume margins ciliolate. Upper glume mucronate, or awned; 1 -awned. Upper glume awn 1–2 mm long.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; hyaline. Fertile lemma oblong; 3.5 mm long; hyaline; 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; 12–20 mm long overall; with twisted column. Column of lemma awn glabrous.

DISTRIBUTION Africa: western Indian ocean.

NOTES Andropogoneae. Vorontsova 2013.

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