Amaranthus muricatus |
Amaranthus scleropoides |
|
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African amaranth, muricate amaranth |
bonebract amaranth, bonebract pigweed |
|
Habit | Plants annual or short-lived perennial, glabrous or slightly pubescent near tips. | Plants annual, glabrous. |
Stems | ascending or prostrate, much-branched from stout rootstock, 0.1–0.4 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. |
ascending to prostrate, erect when young, or main stems ± erect, branched proximally, 0.1–0.6 m. Leaves: petiole equaling or 1/2 as long as blade; blade elliptic, oblanceolate to lanceolate, (0.5–)1–3(–3.5) × 0.3–2 cm, base tapering, margins entire, plane to slightly undulate, apex broadly rounded or emarginate. |
Bracts | of pistillate flowers linear, 0.7–1.2 mm, 1/2–2/3 as long as tepals. |
of pistillate flowers keeled (only A. scleropoides and A. crassipes have keeled bracts), ovate-triangular, minute. |
Inflorescences | terminal, compact pyramidal panicles and axillary glomerules, erect or reflexed, green, leafless at least distally. |
axillary clusters borne from base to top, axes thickened and inflated, becoming indurate at maturity (only in A. scleropoides and A. crassipes). |
Staminate flowers | intermixed with pistillate or at tips of inflorescences; tepals 5; stamens 5. |
intermixed with pistillate; tepals 5, membranaceous; stamens 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, narrowly spatulate, slightly clawed, with expanded blade, equal or subequal, (1.2–)1.5–2.5 mm, apex acute to apiculate; claws indurate at maturity; style branches spreading; stigmas 2–3. |
Seeds | black, lenticular, 1–1.2 mm diam., semiglossy. |
dark brownish black to black, compressed-ovoid to broadly lenticular, 0.9–1.1 mm diam., shiny. |
Utricles | compressed, subglobose, 1.7–2 mm, ± equaling or slightly exceeding tepals, muricate, indehiscent. |
orbicular to compressed-obovoid, 1.1–1.5 mm, shorter than tepals, smooth to tuberculate in distal 1/2, dehiscence regularly circumscissile. |
Amaranthus muricatus |
Amaranthus scleropoides |
|
Phenology | Flowering summer–fall. | Flowering summer–fall. |
Habitat | Waste places, on ballast | Seasonally wet, disturbed habitats |
Elevation | 0 m (0 ft) | 0-1300 m (0-4300 ft) |
Distribution |
AL; s South America (Argentina, Paraguay, Uruguay) [Introduced in North America; introduced in s Europe, s Africa, Australia, and other regions] |
OK; TX; Mexico (Tamaulipas) |
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.) |
A hybrid between Amaranthus crassipes and A. scleropoides was recently described as A. ×texensis Henrickson and reported from southeastern Texas (J. Henrickson 1999). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 4, p. 431. | FNA vol. 4, p. 433. |
Parent taxa | Amaranthaceae > Amaranthus > subg. Albersia | Amaranthaceae > Amaranthus > subg. Albersia |
Sibling taxa | ||
Synonyms | Euxolus muricatus | A. blitoides var. scleropoides |
Name authority | (Moquin-Tandon) Hieronymus: Pl. Diaph. Fl. Argent., 227. (1882) | Uline & W. L. Bray: Bot. Gaz. 19: 316. (1894) |
Web links |