Amaranthus muricatus |
Amaranthus polygonoides |
|
---|---|---|
African amaranth, muricate amaranth |
smartweed amaranth, tropical amaranth |
|
Habit | Plants annual or short-lived perennial, glabrous or slightly pubescent near tips. | Plants annual, glabrescent proximally, pubescent distally, becoming glabrous at maturity. |
Stems | ascending or prostrate, much-branched from stout rootstock, 0.1–0.4 m. |
erect-ascending to prostrate, branched mostly at base and in proximal 1/2, 0.1–0.5 m. |
Leaves | petiole to 1/2 as long as blade; blade linear to narrowly lanceolate, 1.5–8 × 0.2–0.5(–1) mm, base tapering, margins entire, plane to undulate, apex obtuse and often emarginate. |
petiole ± equaling blade; blade ovate, obovate-rhombic to narrowly ovate, sometimes lanceolate, 1.5–3(–4) × 0.5–1.5(–2) cm, base cuneate, margins entire to undulate-erose, apex rounded, obtuse, or emarginate, mucronate. |
Bracts | of pistillate flowers linear, 0.7–1.2 mm, 1/2–2/3 as long as tepals. |
of pistillate flowers lanceolate or linear, 1–1.5 mm, 1/2 as long as tepals. |
Inflorescences | terminal, compact pyramidal panicles and axillary glomerules, erect or reflexed, green, leafless at least distally. |
axillary, congested clusters. |
Staminate flowers | intermixed with pistillate or at tips of inflorescences; tepals 5; stamens 5. |
intermixed with pistillate; tepals (4–)5; stamens 2–3. |
Pistillate flowers | tepals 5, narrowly oblanceolate, not clawed, equal, 1.5–2 mm, apex obtuse or subacute; style branches erect; stigmas 3. |
tepals 5, connate in proximal 1/3 (entirely distinct in all other species), with 3 prominent veins abaxially, spatulate or somewhat clawed, equal or subequal, 2–3 mm, apex rounded or retuse, mucronate; style branches somewhat spreading; stigmas 3. |
Seeds | black, lenticular, 1–1.2 mm diam., semiglossy. |
dark reddish brown to black, lenticular, 0.8–1 mm diam., shiny. |
Utricles | compressed, subglobose, 1.7–2 mm, ± equaling or slightly exceeding tepals, muricate, indehiscent. |
cylindric or narrowly turbinate, 2–2.5 mm, ± equaling tepals, smooth proximally or roughened toward tips, indehiscent or tardily dehiscent. |
Amaranthus muricatus |
Amaranthus polygonoides |
|
Phenology | Flowering summer–fall. | Flowering summer–fall. |
Habitat | Waste places, on ballast | Disturbed habitats, coastal areas, near wool-combing mills |
Elevation | 0 m (0 ft) | 0-500 m (0-1600 ft) |
Distribution |
AL; s South America (Argentina, Paraguay, Uruguay) [Introduced in North America; introduced in s Europe, s Africa, Australia, and other regions] |
FL; SC; TX; Mexico; West Indies; n South America [Rarely introduced in Europe and some other regions] |
Discussion | The vernacular name “African amaranth” is sometimes used for this species; it is a misnomer; the species is native to South America and naturalized in Africa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Amaranthus berlandieri often has been recognized as a separate species related to A. polygonoides. J. Henrickson (1999) clarified the confusion that existed in earlier descriptions of these two taxa and showed that the main characters used for their separation (dehiscent versus indehiscent utricles, leaf shape, etc.) are inconsistent and cannot be applied for segregation of two independent species. The subspecies rank may be more appropriate for A. berlandieri, as was suggested by A. Thellung (1914–1919). The relationships between these taxa of the A. polygoniodes aggregate require additional study; in the present treatment we follow the solution proposed by Henrickson. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 4, p. 431. | FNA vol. 4, p. 432. |
Parent taxa | Amaranthaceae > Amaranthus > subg. Albersia | Amaranthaceae > Amaranthus > subg. Albersia |
Sibling taxa | ||
Synonyms | Euxolus muricatus | A. berlandieri |
Name authority | (Moquin-Tandon) Hieronymus: Pl. Diaph. Fl. Argent., 227. (1882) | Linnaeus: Pl. Jamaic. Pug., 27. (1759) |
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