Amaranthus muricatus |
Amaranthus wrightii |
|
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African amaranth, muricate amaranth |
Wright's amaranth |
|
Habit | Plants annual or short-lived perennial, glabrous or slightly pubescent near tips. | Plants glabrous or nearly so. |
Stems | ascending or prostrate, much-branched from stout rootstock, 0.1–0.4 m. |
erect or ascending, often whitish or tinged with red, simple to sparingly branched distally, or occasionally basally, 0.2–1 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 shorter than to ± equaling blade; blade rhombic-ovate to elliptic-lanceolate, 1.5–6 × 0.5–3 cm, base broadly to narrowly cuneate, margins entire, plane to slightly undulate, apex obtuse to subacute, or shallowly emarginate, with terminal mucro. |
Bracts | of pistillate flowers linear, 0.7–1.2 mm, 1/2–2/3 as long as tepals. |
linear-lanceolate to subulate, to 2 times as long as tepals, apex spinescent. |
Inflorescences | terminal, compact pyramidal panicles and axillary glomerules, erect or reflexed, green, leafless at least distally. |
terminal and axillary in distal part of plant, erect, usually reddish green, branched, leafless at least distally, short and thick. |
Staminate flowers | intermixed with pistillate or at tips of inflorescences; tepals 5; stamens 5. |
few at tips of inflorescences; tepals 5; stamens 4–5. |
Pistillate flowers | tepals 5, narrowly oblanceolate, not clawed, equal, 1.5–2 mm, apex obtuse or subacute; style branches erect; stigmas 3. |
tepals 5, spatulate-linear, not clawed, subequal or unequal, 1.5–2 mm, membranaceous, apex emarginate or retuse to obtuse, outer tepals with apex rarely subacute; style branches shorter than body of fruit; stigmas 3. |
Seeds | black, lenticular, 1–1.2 mm diam., semiglossy. |
dark reddish brown to nearly black, lenticular to subglobose-lenticular, 1 mm diam., smooth, shiny. |
Utricles | compressed, subglobose, 1.7–2 mm, ± equaling or slightly exceeding tepals, muricate, indehiscent. |
subglobose to broadly obovoid, 1.3–2 mm, equal or subequal to tepals, smooth or slightly rugose, dehiscence regularly circumscissile. |
Amaranthus muricatus |
Amaranthus wrightii |
|
Phenology | Flowering summer–fall. | Flowering summer–fall. |
Habitat | Waste places, on ballast | Naturally disturbed habitats, streambanks, canyons, semideserts |
Elevation | 0 m (0 ft) | 500-2000 m (1600-6600 ft) |
Distribution |
AL; s South America (Argentina, Paraguay, Uruguay) [Introduced in North America; introduced in s Europe, s Africa, Australia, and other regions] |
AZ; CO; NM; TX |
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 wrightii seems to be closely related to A. retroflexus. In some herbaria the specimens of A. acanthochiton J. D. Sauer (previously known as Acanthochiton wrightii Torrey, see above) were mechanically “transferred” to Amaranthus and erroneously placed in folders as “Amaranthus wrightii.” That confusion was caused by the identical species epithets; these two taxa are dramatically different morphologically. Amaranthus wrightii may also occur in adjacent Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 4, p. 431. | FNA vol. 4, p. 422. |
Parent taxa | Amaranthaceae > Amaranthus > subg. Albersia | Amaranthaceae > Amaranthus > subg. Amaranthus |
Sibling taxa | ||
Synonyms | Euxolus muricatus | |
Name authority | (Moquin-Tandon) Hieronymus: Pl. Diaph. Fl. Argent., 227. (1882) | S. Watson: Proc. Amer. Acad. Arts 12: 275. (1877) |
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