Amaranthus viridis |
Amaranthus graecizans |
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green amaranth, slender amaranth, tropical green amaranth |
Mediterranean amaranth, spreading pigweed, tumbleweed |
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Habit | Plants annual, sometimes short-lived perennial in tropics and subtropics, glabrous. | Plants annual, pubescent in distal parts or becoming glabrescent at maturity. |
Stems | erect, simple or with lateral branches (especially distally), 0.2–1 m. Leaves: petiole 1/2–11/2 as long as blade; blade rhombic-ovate or ovate, 1–7 × 0.5–5 cm, base rounded, cuneate, or attenuate, margins entire, plane, apex obtuse, rounded, or emarginate, mucronate. |
erect to ascending or decumbent, branched at or distal to base, 0.1–0.9 m. Leaves: petiole variable in length; blade lanceolate to nearly linear or rhombic-ovate to elliptic-ovate, (1.5–)2–4(–5) × 1–3 cm, base cuneate to broadly cuneate, margins entire, plane, rarely indistinctly undulate, apex subacute to obtuse or emarginate, mucronulate. |
Bracts | of pistillate flowers ovate to lanceolate, 1 mm, shorter than tepals. |
lanceolate, subspinescent, 1.5–2 mm, shorter or slightly longer than tepals. |
Inflorescences | slender spikes aggregated into elongate terminal panicles, also from distal axils, green, leafless at least distally. |
axillary glomerules, green. |
Staminate flowers | inconspicuous, mostly at tips of inflorescences; tepals 3; stamens 3. |
intermixed with pistillate; tepals 3, equal or subequal; stamens 3. |
Pistillate flowers | tepals 3, narrowly elliptic, obovate-elliptic or spatulate, not clawed, ± equal, 1.2–1.7 mm, apex rounded or nearly acute, mucronate or not; style branches erect; stigmas 3. |
tepals 3, erect, elliptic to lanceolate-elliptic, equal or subequal, 1.5–2 mm, apex short-acuminate; style branches slightly spreading; stigmas (2–)3. |
Seeds | black or dark brown, subglobose to thick-lenticular, 1 mm diam., minutely punctulate, rather dull. |
black, lenticular, 1–1.3(–1.6) mm diam., smooth or indistinctly punctate. |
Utricles | ovoid to compressed-ovoid, 1–1.6 mm, equaling or slightly exceeding tepals, prominently or faintly rugose, indehiscent. |
subglobose to broadly elliptic, 2–2.5 mm, slightly rugose, dehiscence regularly circumscissile, rarely irregularly dehiscent. |
Amaranthus viridis |
Amaranthus graecizans |
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Phenology | Flowering summer–fall. | Flowering summer–fall. |
Habitat | Fields, railroads, lawns, gardens, waste areas, other disturbed habitats | On ballast |
Elevation | 0-1000 m (0-3300 ft) | 0 m (0 ft) |
Distribution |
AL; AR; AZ; FL; GA; LA; MA; MI; MS; NC; NM; NY; OK; PA; SC; TN; TX; VA; native to South America [Introduced in North America; introduced in tropical and subtropical regions worldwide]
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NJ; native to Eurasia (Mediterranean area, s Asia); n Africa [Introduced in North America; locally introduced in Australia]
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Discussion | In North America the name Amaranthus graecizans has been constantly misapplied to the common North American taxa A. albus and A. blitoides. Consequently, A. graecizans has been excluded from lists of North American plants. Recently, herbarium specimens (casual aliens collected in 1879 on ballast in Camden, New Jersey) of A. graecizans subsp. sylvestris were discovered (M. Costea et al. 2001b). Probably, the species disappeared in North America long ago, but, considering the long history of misidentification and confusion, there is also some chance that it may occur locally as an introduced species. Three subspecies are usually recognized within Amaranthus graecizans in the Old World: subsp. graecizans, subsp. sylvestris (Villars) Brenan, and subsp. thellungianus (Nevski) Gusev. Only subsp. sylvestris, characterized by rhombic-ovate to elliptic-ovate leaves (as compared to lanceolate to almost linear leaves in subsp. graecizans) and comparatively large seeds has so far been reported from North America. Despite its superficial similarity to Amaranthus albus and A. blitoides, A. graecizans seems to be more closely related to other Old World taxa with trimerous flowers. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 4, p. 429. | FNA vol. 4. |
Parent taxa | Amaranthaceae > Amaranthus > subg. Albersia | Amaranthaceae > Amaranthus > subg. Albersia |
Sibling taxa | ||
Synonyms | A. gracilis | |
Name authority | Linnaeus: Sp. Pl. ed. 2, 2: 1405. (1763) | Linnaeus: Sp. Pl. 2: 990. (1753) |
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