Andropogon pusillus

HABIT Annual; culms solitary, or caespitose. Culms geniculately ascending, or decumbent; 5–15 cm long. Leaf-sheaths hirsute; with tubercle-based hairs. Ligule an eciliate membrane. Leaf-blades 2–3 cm long; 2–3 mm wide. Leaf-blade surface hirsute. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; embraced at base by subtending leaf. Spatheole lanceolate; 3–4 cm long.

Racemes 2; paired; deflexed; 2.5–5 cm long; bearing few fertile spikelets; bearing 2–4 fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis internodes filiform; 3 mm long. Rhachis internode tip transverse; flat; with simple rim. Raceme-bases linear; subequal; 1 mm long; pilose; hairy in axils; persistent.

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

STERILE SPIKELETS Basal sterile spikelets well-developed; 2 in number (lower raceme); 0 in upper raceme.

Companion sterile spikelets well-developed; comprising 2 subequal glumes without lemmas, or containing empty lemmas; lanceolate; dorsally compressed; 7–8 mm long; longer than fertile; persistent. Companion sterile spikelet glumes chartaceous; keeled; without depressions, or pitted (2 pits); dentate; 2 -fid; acute; awned; one glume awned; with 6–8 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 oblong; dorsally compressed; 5–6 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base obtuse; attached transversely. Spikelet callus hairs 1–2 mm long.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; chartaceous, or herbaceous; 2-keeled; keeled above; keeled laterally. Lower glume primary vein scabrous. Lower glume intercarinal veins distinct; 4–6 in number. Lower glume surface convex and with a longitudinal median groove; pitted (2 pits). Lower glume apex dentate; 2 -fid. Upper glume oblong; chartaceous; 1-keeled; keeled above; 3 -veined. Upper glume apex dentate; 2 -fid; awned; 1 -awned. Upper glume awn 3–6 mm long.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; hyaline; 2 -veined. Fertile lemma oblong; hyaline; without keel. Lemma apex lobed; 2 -fid; incised 0.33 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 35–45 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

DISTRIBUTION Africa: west tropical and west-central tropical.

NOTES Andropogoneae. FTA.

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