Paspalum distichum L.
Family: Poaceae, Tribe: Paniceae
Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)
Digitaria paspaloides Michx., Panicum digitarioides Raspail ex Kunth
Pertinent Common Names (particularly those used in California; go to GRIN for other common names)
knotgrass
Primary Disseminule Type
spikelet
Description (diagnostics are in brown)
Spikelet solitary (rarely paired), broadly elliptic to ovate or obovate, mildly dorsally compressed, plano-convex (D-shaped in profile), 2.4–4 mm long x 1.1–1.6 mm wide x 0.8–1 mm thick, straw-colored at maturity, sometimes partially purple, falling entire (disarticulation below glumes), consisting of one fertile floret and one basal sterile floret without rachilla extension.
Lower glume absent or when rarely present, ovate to triangular, <2.5 mm long, 0.1–0.2 length of spikelet, hyaline, 0–1-veined. Upper glume elliptic, same length as spikelet, reaching apex of floret, thinner than fertile lemma, coriaceous, without keel, 3–5-veined, surface puberulous, apex acute.
Sterile lemma similar to upper glume (elliptic, same length as spikelet, coriaceous, without keel, 3–5-veined, apex acute), surface glabrous. Sterile palea absent or when rarely present, narrow, short, hyaline, 2-veined.
Fertile lemma elliptic to ovate, convex in profile, 2–3 mm long, pallid, indurate, without keel, faintly 5-veined, surface finely punctulate-striolate, shiny, margins involute, apex acute, often with a tuft of short hairs.
Fertile palea similar to fertile lemma (indurate, margins involute), flat.
Caryopsis oblong, dorsally compressed, 1.5–2.1 mm long x 1.2–1.3 mm wide, yellowish-brown, embryo <0.33 length of caryopsis, hilum oval, dark.
Similar Species
Risk Assessment (codes in yellow or red indicate cause for concern; assessments are current as of mid-2011; click AUQP, NZBORIC, or NZBPI for access to the most recent versions of these databases and possible assessment changes)
AUQP, NZBORIC, NZBPI