Amaranthus cruentus
Amaranthus cannabinus
blood amaranth, caterpillar amaranth, purple amaranth, red amaranth
salt marsh pigweed, salt-marsh water-hemp, tidal-marsh water-hemp, tidalmarsh amaranth, water-hemp pigweed
erect, green or reddish purple, branched distally, mostly in inflorescence, to nearly simple, 0.4–2 m. Leaves: petiole 1/2 as long as to ± equaling blade;
blade rhombic-ovate or ovate to broadly lanceolate, 3–15(–20) × 1.5–10(–15) cm, occasionally larger in robust plants, base cuneate to broadly cuneate, margins entire, plane, apex acute or subobtuse to slightly emarginate, with mucro.
erect, branched, stout, usually 1–3 m. Leaves: petiole 1/2 length of blade;
blade lanceolate or narrowly lanceolate to linear, to 20 × 4 cm, base narrowly cuneate, margins entire, plane to slightly undulate, apex acute to acuminate.
narrowly spathulate, 2–3 mm, equaling or slightly longer than tepals, apex short-spinescent.
of pistillate flowers 1.5 mm; of staminate flowers with midribs not prominent, scarcely excurrent, shorter than 1 mm.
terminal and axillary, erect, reflexed, or nodding, usually dark red, purple, or deep beet-red, less commonly almost green or greenish red, leafless at least distally, large and robust.
mostly terminal, narrow spikes or thyrses, usually interrupted, linear.
at tips of inflorescences;
tepals 5;
stamens (4–)5.
tepals 5, without prominent midribs, equal, 2.5–3 mm, apex obtuse to indistinctly mucronulate in outer tepals;
stamens 3–5.
tepals 5, oblong to lanceolate, not clawed, equal or subequal, 1.5–3 mm, apex acute;
style branches erect or slightly reflexed;
stigmas 3.
tepals absent or 1–2 and rudimentary;
style branches ± erect;
stigmas 3–5.
usually white or ivory, with reddish or yellowish tint, sometimes dark brown to dark reddish brown, broadly lenticular to elliptic-lenticular, 1.2–1.6 mm diam., smooth or indistinctly punctate.
reddish brown to dark brown, 2–3 mm diam., shiny.
obovoid to elongate-obovoid, 2–2.5 mm, smooth or slightly rugose distally, dehiscence regularly circumscissile.
often black, with 3(–5) longitudinal ridges corresponding to 3–5 style branches, ovoid or obovoid, 2.5–4 mm (exceeding tepals, when present), somewhat fleshy, smooth (slightly rugose, especially in herbarium specimens).
Amaranthus cruentus
Amaranthus cannabinus
Amaranthus cruentus is cultivated as ornamental and pseudocereal almost worldwide from tropical to warm-temperate regions. While reported as naturalized in several states, most specimens identified as this species are referable to A. hybridus or other native species. Escaped plants of A. cruentus sometimes occur near places of cultivation (see note under A. caudatus). No attempt has been made to summarize distribution data for such escapes.
Amaranthus cruentus originated from A. hybridus (most probably in cultivation in Central America), with which it shares almost all major morphologic characteristics. Inclusion of cultivated forms in A. hybridus in a broad sense is thus rather justified. Cultivated species traditionally have been treated as separate taxa in horticultural and agricultural literature, and we prefer to maintain the current convenient usage of these names.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Reports of Amaranthus cannabinus from southern Florida and the Gulf Coastal Plain are the result of misidentifications of A. australis. According to J. D. Sauer (1955), plants of A. cannabinus from northern coastal Atlantic Florida are atypical and probably represent hybrid populations transitional toward A. australis.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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