Amaranthus hybridus L.
Family: Amaranthaceae
Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)
none
Pertinent Common Names (particularly those used in California; go to GRIN for other common names)
smooth pigweed
Primary Disseminule Type
seed
Description (diagnostics are in brown)
Fruit a dehiscent (circumscissile) utricle, obovoid, 1.5–2.5 mm long, smooth proximally, rugose or verrucose distally, with 5 attached tepals (tepals lanceolate to linear, subequal or unequal, 1.5–3 mm long, apex acute to acuminate narrowing into an aristate tip), with subtending sharply-pointed bracts 2–4 mm long, containing 1 seed.
Seed round to elliptic in outline, compressed with an obtuse marginal rim, cross-section lens-shaped to barely fusiform, with a protruding notch along the margin where hilum occurs and from which a shallow depression runs inward for a short distance, 1–1.5 mm diameter x 0.4–0.6 mm thick. Surface shiny, ± smooth (under magnification, looking cobblestone-like, as well as pitted and punctate in some spots), dark reddish-brown to black.
Hilar region round to elliptic, consisting of a round to linear opening between two semi-circular scars.
Embryo annular, surrounding copious perisperm.
Similar Species
Similar Species Comparison Chart
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