Aristida tenuissima

HABIT Annual, or perennial; caespitose; clumped densely. Culms erect; slender; 5–54 cm long; 0.3–0.5 mm diam.; wiry. Lateral branches lacking, or sparse. Leaves mostly basal. Leaf-sheaths striately veined; glabrous on surface. Leaf-sheath oral hairs scanty. Ligule a fringe of hairs. Leaf-blades straight, or curled; filiform; convolute; 2–30 cm long; 0.5–0.8 mm wide. Leaf-blade surface hirsute; densely hairy; hairy abaxially. Leaf-blade apex acute.

INFLORESCENCE Inflorescence a panicle; comprising 3–20 fertile spikelets.

Panicle open; linear, or oblong; 3–9 cm long; 0.5–2 cm wide; bearing few spikelets. Primary panicle branches appressed, or ascending; 1–2 -nate; indistinct the panicle almost racemose, or simple; bearing 1–3 fertile spikelets on each lower branch. Panicle branches glandular; smooth, or scaberulous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear; laterally compressed; 5–6 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.4 mm long; pilose; obtuse. Floret callus hairs 0.5–1 mm long.

GLUMES Glumes persistent; similar; reaching apex of florets, or exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 3.5–5 mm long; 0.75–1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent. Lower glume surface smooth, or asperulous. Lower glume apex acuminate; muticous, or mucronate. Upper glume lanceolate; 5–6 mm long; 1–1.1 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume primary vein scabrous. Upper glume lateral veins absent. Upper glume surface smooth, or asperulous. Upper glume apex truncate; muticous, or mucronate.

FLORETS Fertile lemma lanceolate; subterete; 4–6 mm long; coriaceous; mid-green, or purple; without keel; 3 -veined. Lemma surface scaberulous. Lemma margins involute; covering most of palea. Lemma apex acute; awned; 1 -awned, or 3 -awned. Principal lemma awn geniculate (when single), or 3-branched; 7–16 mm long overall; with 4–10 mm long limb; with twisted column; persistent. Column of lemma awn 3–6 mm long. Lateral lemma awns when present 3–5 mm long; shorter than principal. Palea 0.1 length of lemma; without keels.

FLOWER Anthers 3.

DISTRIBUTION Africa: western Indian ocean.

NOTES Aristideae. Vorontsova 2013.

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