Amaranthus muricatus
Amaranthus crassipes
African amaranth, muricate amaranth
clubfoot amaranth, spreading amaranth, tropical spreading amaranth
ascending or prostrate, much-branched from stout rootstock, 0.1–0.4 m.
prostrate or weakly ascending, erect when young, branched mostly from base, 0.1–0.6 m.
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 nearly 1/2 as long as blade;
blade broadly elliptic, obovate, orbiculate, or oblanceolate, (0.5–)1–3(–4.5) × 0.3–2(–2.5) cm, base cuneate, margins entire, plane to undulate, apex broadly rounded or emarginate.
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), deltate, 0.5–0.9 mm.
terminal, compact pyramidal panicles and axillary glomerules, erect or reflexed, green, leafless at least distally.
axillary clusters borne from base to apex, axes much thickened, appearing inflated, becoming indurate at maturity (only in A. scleropoides and A. crassipes).
intermixed with pistillate or at tips of inflorescences;
tepals 5;
stamens 5.
intermixed with pistillate;
tepals 5, membranaceous;
stamens 3(–5).
tepals 5, narrowly oblanceolate, not clawed, equal, 1.5–2 mm, apex obtuse or subacute;
style branches erect;
stigmas 3.
tepals (4–)5, narrowly spatulate, clawed, with small expanded blade, equal or subequal, 2–3 mm, apex rounded and apiculate;
claws becoming indurate and scarious at maturity;
style branches spreading;
stigmas usually 2(–3), almost sessile.
black, lenticular, 1–1.2 mm diam., semiglossy.
dark brownish or reddish black to black, compressed-ovoid to broadly lenticular, 1–1.4 mm diam., shiny.
compressed, subglobose, 1.7–2 mm, ± equaling or slightly exceeding tepals, muricate, indehiscent.
obovoid to compressed-obovoid, 1.4–2 mm, shorter than tepals, prominently muricate (especially in distal 1/2), indehiscent.
Amaranthus muricatus
Amaranthus crassipes
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.)
Two varieties have been distinguished by J. Henrickson (1999) within Amaranthus crassipes: var. crassipes with leaf blades nearly orbiculate to ovate (obovate) and conspicuous veins on the green to yellow-green abaxial leaf surface; and var. warnockii (I. M. Johnston) Henrickson (= A. warnockii I. M. Johnston) with narrower oblanceolate grayish leaves with less distinct venation on the abaxial leaf surfaces. In Henrickson’s treatment, var. crassipes occurs mostly in the coastal areas (and is also reported for Arizona), while var. warnockii is reported from inland southwestern Texas and the Chihuahuan Desert region (Mexico: Coahuila, Chihuahua). We have not seen material of the new varieties and cannot evaluate their validity.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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