Diheteropogon filifolius

HABIT Perennial; caespitose. Butt sheaths persistent and investing base of culm; with compacted dead sheaths, or fibrous dead sheaths. Culms 15–23 cm long. Ligule an eciliate membrane. Leaf-blades filiform, or linear; flat, or involute; 10–50 cm long; 0.5–6(–16) mm wide.

INFLORESCENCE Synflorescence simple, or compound; scanty. Inflorescence composed of racemes; terminal, or terminal and axillary; subtended by a spatheole. Spatheole lanceolate; herbaceous.

Racemes 2; paired; 2.5–14(–17) cm long. Rhachis fragile at the nodes; ciliate on margins. Rhachis internodes linear, or clavate. Rhachis internode tip crateriform; with simple rim. Raceme-bases filiform, or linear.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; ciliate.

STERILE SPIKELETS Basal sterile spikelets well-developed; 2–22 in number (lower raceme); 0 in upper raceme, or 6–22 in upper raceme; sessile and pedicelled; equalling fertile.

Companion sterile spikelets well-developed; male; lanceolate; dorsally compressed; 12–25 mm long; longer than fertile; deciduous with the fertile. Companion sterile spikelet glumes herbaceous; wingless, or winged on keels; distinctly veined; muticous, or awned; one glume awned; with 0–8 mm long awn. Companion sterile spikelet lemmas 2; enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets linear; subterete, or dorsally compressed; 6–15 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus linear; 2.5–5 mm long; pubescent; base pungent; inserted.

GLUMES Glumes dissimilar; firmer than fertile lemma. Lower glume linear, or lanceolate; 1 length of spikelet; coriaceous; 2-keeled; keeled dorsally; keeled sharply, or obtusely. Lower glume lateral veins dissociated from keel, or several in each keel; intercarinal veins absent. Lower glume surface concave, or with a longitudinal median groove, or deeply depressed. Upper glume linear; 3 -veined. Upper glume margins ciliate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret hyaline; 2 -veined; ciliate on margins. Fertile lemma linear, or oblong; hyaline; without keel; 3 -veined. Lemma margins ciliate; hairy above. Lemma apex lobed; 2 -fid; incised 0.66 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; bigeniculate; 30–70(–150) mm long overall; with twisted column. Column of lemma awn puberulous. Palea present, or absent or minute; hyaline; 2 -veined. Palea keels ciliolate.

DISTRIBUTION Africa: west tropical, west-central tropical, east tropical, southern tropical, and south.

NOTES Andropogoneae. = Diheteropogon grandiflorus. FTEA 1997.

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