Cenchrus spinifex Cav.
Family: Poaceae, Tribe: Paniceae
Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)
Cenchrus incertus M. A. Curtis, C. pauciflorus Benth.
Pertinent Common Names (particularly those used in California; go to GRIN for other common names)
Primary Disseminule Type
spikelets surrounded by a spiny cupule
Description (diagnostics are in brown)
Disseminule consists of a cluster of 2–4 spikelets enclosed in a cupule of mostly fused bristles (i.e., a spiny bur). Bur is ovoid to globose, 5.5–10.2 mm long x 2.5–5 mm wide, glabrous or pubescent, base obconical. Bristles 8–40 in one or two whorls, flattened, 2–5.8 mm long x 1–2 mm wide, fused for at least half their length, rigid, purplish.
Spikelet ovate, dorsally compressed, 3.5–5.9 mm long x 1–2.5 mm wide, glabrous, acuminate, consisting of a basal sterile floret, a fertile floret, and no rachilla. Lower glume ovate, 1–3.3 mm long, 0.33–0.5 length of spikelet, membranous, without keel, 1-veined, apex obtuse or acute. Upper glume ovate, (2.8)3.5–5 mm long, membranous, without keel, 5–7-veined, apex obtuse or acute.
Sterile lemma ovate, 3–5(5.9) mm long, same length as spikelet, membranous, 5–7-veined, apex acute. Sterile palea somewhat reduced.
Fertile lemma ovate, 3.4–5.8(6) mm long, coriaceous, much thinner on margins, without keel, 3-veined, margins flat, apex acute.
Fertile palea subequal to fertile lemma, coriaceous.
Caryopsis broadly ovate, dorsally compressed, 1.3–3 mm long, brown, embryo >0.75 length of caryopsis, hilum round, black.
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, AUWP, NZWP, NZBORIC, NZBPI