Amaranthus hybridus
Amaranthus pumilus
green amaranth, green pigweed, hybrid amaranth, slender pigweed, slim amaranth, smooth amaranth, smooth pigweed
coast amaranth, sea-side amaranth, seabeach amaranth
erect, green or sometimes reddish purple, rarely under-developed plants ascending, branched to nearly simple, 0.3–2(–2.5) m.
prostrate to ascending (often forming mats), red, much-branched, 0.1–0.4(–0.5) m, fleshy.
petiole 1/2 as long as to equaling blade;
blade ovate, rhombic-ovate, or lanceolate, (2–)4–15 × (1–)2–6 cm, base cuneate to broadly cuneate, margins entire, apex acute to obtuse, with mucro.
clustered near tips of branches;
petiole 5–10 mm;
blade orbiculate, broadly ovate or obovate, 1–1.5 cm × 1–1.5 cm, fleshy, base broadly cuneate to tapering, margin entire, plane or slightly undulate, apex broadly rounded to obtuse, mucronate.
lanceolate-linear to subulate, 2–3.5(–4) mm, subequal to or 2 times as long as tepals, apex spinescent.
of pistillate flowers ovate or elliptic, 1.2–2 mm, 1/2 as long as tepals.
terminal and axillary, erect or reflexed, occasionally nodding, green or olive green, occasionally with silvery or reddish purple tint, leafless at least distally, terrminal inflorescence often slightly nodding with numerous shorter branches at base.
dense axillary glomerules, green.
at tips of inflorescences;
tepals 5;
stamens (4–)5.
intermixed with pistillate;
tepals 5;
stamens 5.
tepals 5, lanceolate to lanceolate-linear, subequal or unequal, 1.5–3 mm, membranaceous, apex acute or acuminate, gradually narrowing into aristate tip;
style branches erect, shorter than body of fruit;
stigmas 3.
tepals 5, linear to narrowly oblanceolate, slightly unequal, 2.5–4 mm, margins entire, apex obtuse;
style branches erect;
stigmas 3.
black to dark reddish brown, lenticular to lenticular-globose, 1–1.3 mm, smooth, shiny.
dark reddish brown, lenticular, 2.5 mm diam., glossy.
obovoid or elongate-ovoid, 1.5–2.5 mm, shorter than tepals, smooth proximally, lid verrucose or rugose, dehiscence regularly circumscissile, or rarely in some presumably hybrid forms, irregularly dehiscent or indehiscent.
ovoid, 4–6 mm, exceeding tepals, fleshy, smooth or slightly rugose, longitudinally wrinkled on drying, indehiscent.
Amaranthus hybridus
Amaranthus pumilus
Originally a riverside pioneer in eastern North America, now Amaranthus hybridus is extremely abundant in agricultural fields and other disturbed habitats. Related cultivated species have been reported from the flora area, including A. caudatus, A. hypochondriacus, and A. cruentus; there is no evidence that they are established; specimens identified as these species are often variants of A. hybridus.
Distribution of Amaranthus hybridus in North America needs clarification because the name was misapplied to other species, notably A. powellii, and specimens of A. retroflexus, A. powellii, and A. hybridus are frequently interchangeably misidentified. Forms of A. hybridus and A. powellii with reddish inflorescences are often misidentified as escaped and hence presumably naturalized, cultivated species A. caudatus Linnaeus, A. hypochondriacus Linnaeus, and A. cruentus Linnaeus.
Amaranthus hybridus is extremely variable. In particular, there are numerous North American specimens with subobtuse tepals and thick inflorescences, suggesting hybridization with A. retroflexus. In Europe such presumably hybrid forms are known as A. ×ozanonii Thellung (A. Thellung 1914–1919).
A new, presumably hybridogenous taxon, Amaranthus ×tucsonensis Henrickson, was recently described from Arizona (J. Henrickson 1999). It was suggested that one of its parents is A. hybridus; the other parental species (probably a species with obtuse or spatulate tepals) remains unknown. The problem of proper taxonomic position and origin of A. ×tucsonensis needs further study.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Of conservation concern.
Amaranthus pumilus is a globally and federally threatened species (Global Heritage Status Rank G2; National Heritage Status Rank N2) originally restricted to dunes and barrier island beaches along the Atlantic Ocean from southern Massachusetts to South Carolina. It has been eliminated from two-thirds of its former range, being last reported from Massachusetts in 1849, from Rhode Island in 1856, from New Jersey in 1913, and from Virginia in 1972 (S. Ramsey et al. 2000). As of fall 2003, extant populations are known only from Long Island, New York, Delaware, Maryland, North Carolina, and South Carolia. Many threats exist, including construction of sea walls and dune fencing, development, heavy recreational use, and off-road vehicle traffic. It is difficult to afford protection because of the dynamic nature of the habitat and the fugitive nature of the biology of the species. “Fugitive” refers to the fact that the species does not necessarily occur throughout its potential range at any given time (S. E. Clemants 1992).
Amaranthus pumilus is in the Center for Plant Conservation’s National Collection of Endangered Plants.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
Go Botany, 
IL Wildflowers, 
KS Wildflowers, 
LA Plants, 
MD Biodiversity, 
MI Flora, 
MN Wildflowers, 
MO Plants, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
