Digitaria ischaemum (Schreb.) Muhl.
Family: Poaceae, Tribe: Paniceae
Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)
Digitaria glabra Beauv., D. humifusa Pers.
Pertinent Common Names (particularly those used in California; go to GRIN for other common names)
smooth crabgrass
Primary Disseminule Type
spikelet
Description (diagnostics are in brown)
Spikelets occurring in homomorphic fertile triplets, with disarticulation at base of each spikelet. Spikelet nearly sessile (pedicel short), narrowly elliptic, dorsally compressed, 1.7–2.5 mm long, ca.1 mm wide, consisting of one fertile floret and one basal sterile lemma without rachilla extension.
Lower glume lacking or reduced to a translucent veinless membranous rim (< 0.2 mm long). Upper glume elliptic, 1.3–2.3 mm long, 0.9 length of spikelet, membranous, 3-veined, veins ribbed, surface pubescent with clavate hairs, apex acute.
Sterile lemma elliptic, same length as spikelet, membranous, 7-veined, veins unequally spaced, ribbed, surface pubescent between veins with clavate hairs, apex obtuse.
Fertile lemma elliptic, dark brown at maturity, cartilaginous, shiny, much thinner on margins, 1.7–2.5 mm long, without keel, margins flat (covering most of palea), apex acute.
Fertile palea brown, cartilaginous, shiny.
Caryopsis ovate or elliptic to oblong, 1–1.5 mm long x ca. 0.8 mm wide, translucent with yellowish highlights, embryo >0.33 length of caryopsis, hilum oval to round.
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, NZWP, NZBORIC, NZBPI