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Amaranthus hybridus
SMOOTH PIGWEED, GREEN AMARANTH

Higher Taxonomy
Family: AmaranthaceaeView DescriptionDichotomous Key

Common Name: AMARANTH FAMILY
Habit: Annual to subshrub; monoecious and/or dioecious; occasionally spiny; hairs simple (branched). Leaf: blade simple, alternate or opposite, margins entire or serrate; veins pinnate; stipules 0. Inflorescence: axillary or terminal; 3-flowered cymes in dense spikes, heads or panicles; bracts 0 or 1--5, persistent; bractlets 0--2. Flower: bisexual or unisexual, small, green (+- white), yellow or purple; perianth parts 0 or (1)3--5, free or fused basally, scarious or hardened, persistent; stamens 1--5, opposite perianth parts, free or basally fused as a tube, generally unequal, occasionally alternate with appendages on stamen tubes (pseudostaminodes), anthers 2- or 4-chambered; ovary superior, chamber 1; ovule 1 (2--many); style (0)1--3, stigmas 1--3(5). Fruit: utricle; generally with persistent perianth or bracts. Seed: 1 [2+], small, lenticular to spheric, smooth or dotted to striate or tubercled.
Genera In Family: +- 75 genera, 900 species: cosmopolitan, especially disturbed, arid, saline or alkaline soils; some cultivated for food, ornamental; many naturalized, ruderal or agricultural weeds. Note: Amaranthaceae including Chenopodiaceae by some. Polycnemoideae, represented in California by Nitrophila, formerly considered subfamily of Chenopodiaceae, but needs further research. Guilleminea densa (Willd.) Moq. var. aggregata Uline & W.L. Bray is a waif. Froelichia gracilis (Hook.) Moq. is an historical waif.
eFlora Treatment Author: Mihai Costea, except as noted
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: AmaranthusView DescriptionDichotomous Key

Common Name: AMARANTH, PIGWEED
Habit: Annual (short-lived perennial herb); monoecious or dioecious. Stem: prostrate to erect, branched or not. Leaf: alternate, petioled, ovate to linear, tip often +- notched (2-lobed), midvein ending in sharp point, margin entire, flat or wavy. Inflorescence: 3-flowered cymes, in dense axillary clusters, or large, terminal, panicle- or spike-like inflorescence; bract 1, bractlets 0--2, alike, persistent, spine-like to +- leaf-like or +- membranous, at least margins scarious-membranous. Flower: unisexual. Staminate Flower: perianth parts (2)3--5, scarious; stamens (1)2--5, filaments free; pseudostaminodes 0; anthers 4-chambered. Pistillate Flower: perianth parts (1)3--5, membranous or scarious, free, persistent; ovary ovoid, style 0, stigmas 2--3, persistent, slender, papillate; ovule 1, erect. Fruit: circumscissile or indehiscent, ovoid to obovoid, smooth or +- wrinkled, tip +- gradually (abruptly) narrowed to stigmas or beak; walls thin, membranous. Seed: 1, lenticular to +- spheric, round to obovate, smooth, shiny, occasionally obscure-dotted or -net-like, +- white-ivory to brown-red or black.
Species In Genus: +- 70 species: worldwide; weeds, ornamentals, food pls. Etymology: (Greek: unfading, non-withering) Note: Hybrids common, F1 generally with numerous, densely packed bractlets beneath generally sterile pistillate flowers, abnormal-shaped inflorescence with dense, twisted or fan-shaped branches. Unless otherwise noted, descriptions of bracts and flower parts are of pistillate flowers.
Unabridged Note: F1 hybrids have been observed in natural conditions or have been experimentally obtained between any of the following species: Amaranthus hybridus, Amaranthus powellii, Amaranthus retroflexus, Amaranthus tuberculatus, Amaranthus palmeri, Amaranthus caudatus, Amaranthus hypochondriacus, Amaranthus cruentus, Amaranthus spinosus, Amaranthus blitoides, Amaranthus albus. Amaranthus caudatus L., Amaranthus cruentus L., Amaranthus hypochondriacus L. frequently cultivated as ornamentals, occasionally escaping from cultivation. Amaranthus spinosus L. probably not naturalized, uncommon waif.

Amaranthus hybridus L.
NATURALIZED
Habit: Monoecious. Stem: erect, 30--120(200) cm, branched or not, green, hairy distally. Leaf: petiole 30--70 mm; blade (30)50--120 mm, (10)20--60 mm wide, rhombic-ovate or wide-lanceolate, base wedge-shaped, tip acute, margins flat. Inflorescence: terminal, panicle-like, erect or nodding, branches many, thin, flexible, 2.5--7(12) cm, 0.5--1 cm wide (including flowers), green or olive green; bracts 2--4 mm, 1.2--2 × perianth, spine-like, lance-linear. Flower: staminate flowers generally at inflorescence tips, perianth parts 5, 2--3 mm, stamens 5; pistillate perianth parts 5, 1.5--2.5(3) mm, +- = or 1 longer, erect, lance-oblong to linear, tip acute or acuminate; stigma branches 3, erect. Fruit: circumscissile; 1.5--2.2 mm, ovoid to obovoid, irregular-dehiscent or indehiscent, occasionally on same pl, lid strongly wrinkled at base. Seed: 0.9--1.4 mm, lenticular, widely elliptic to round, brown to black, smooth to finely dotted on margin, shiny. Chromosomes: 2n=32.
Ecology: Disturbed areas, agricultural fields; Elevation: < 300 m. Bioregional Distribution: GV, CW, SW; Distribution Outside California: United States, southern Canada; native to eastern North America. Flowering Time: Jun--Nov Note: Naturalized in tropics, subtropics, and temperate regions worldwide.
eFlora Treatment Author: Mihai Costea
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Citation for this treatment: Mihai Costea 2016. Amaranthus hybridus, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=12924, accessed on August 28, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on August 28, 2016.


Geographic subdivisions for Amaranthus hybridus:
GV, CW, SW;
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.