Triplasis americana

HABIT Perennial; caespitose. Culms erect; 30–60 cm long; disarticulating at the nodes. Ligule a fringe of hairs. Leaf-blades flat, or involute; 15–18 cm long; 2–4 mm wide.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; 2–5 cm long; bearing few spikelets. Primary panicle branches simple; bearing 1–2 fertile spikelets on each lower branch.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with a barren rhachilla extension. Spikelets linear; laterally compressed; 10 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes eventually visible between lemmas; pubescent. Floret callus pubescent.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume linear; 0.75 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 0.75 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex acute.

FLORETS Fertile lemma oblong; 5–6 mm long; membranous; keeled; 3 -veined. Lemma midvein pubescent. Lemma lateral veins close to margins. Lemma margins pubescent. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; 5–8 mm long overall; limb pubescent; glabrescent towards tip. Palea 0.75 length of lemma. Palea keels pubescent and with a crest of hairs. Rhachilla extension 0.5 length of fertile floret.

FLOWER Anthers 3.

FRUIT Caryopsis with adherent pericarp; ellipsoid; laterally compressed; plano-convex; dark brown. Embryo projecting below grain.

CLEISTOGENES AND VIVIPARY Cleistogenes present; in lower sheaths.

DISTRIBUTION North America: southeast USA.

NOTES Eragrostideae. WDC.

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