Herbs annual or perennial, rarely subshrubs, covered with vesicular or terete hairs (in several species sometimes also with uniseriate, multicellular hairs), farinose (“mealy”) when dry, rarely glabrous. Leaves alternate, petiolate; leaf blade complanate, margin entire or irregularly serrate or lobed. Inflorescence usually of several flowers forming a glomerule (rarely solitary flowers), these arranged in axillary or terminal spikes, panicles, or dichasia; bracts and bractlets absent. Flowers bisexual or some female. Perianth green, globose, 5-parted, in some species (2 or)3- or 4-parted; segments abaxially slightly fleshy at center or longitudinally keeled, adaxially concave, remaining unchanged in fruit, rarely enlarged or becoming juicy, without appendages. Disk usually absent. Stamens 5 or fewer; filaments sometimes basally united, filiform or capillary; anthers oblong, without an appendage. Ovary globose, slightly depressed, rarely ovoid; ovule subsessile; style obscure or very short; stigmas 2(-5). Fruit a utricle; pericarp membranous or slightly fleshy, adnate to seed or free, indehiscent. Seed horizontal, in some species oblique and/or vertical, ovoid, lenticular, or depressed globose; testa lustrous, leathery, smooth or pitted; embryo annular, semi-annular, or horseshoe-shaped; perisperm copious, farinaceous.

Source: [
• 6
]. 

CHENOPODIUM L.

Hierbas, anuales o perennes; plantas hermafroditas o raramente monoicas. Hojas alternas, generalmente pecioladas, frecuentemente glandulosas o farinosas, a veces glabras. Inflorescencia de flores agrupadas en glomérulos terminales o axilares, flores sésiles o subsésiles; sépalos (3–) 5, iguales o subiguales; estambres con filamentos aplanados, anteras dorsifijas; ovario súpero, estigmas 2–5, filiformes o subulados, generalmente sésiles o subsésiles. Fruto un utrículo con pericarpo libre o adherido a la semilla; semilla lenticular, horizontal o vertical, embrión parcial o completamente anular.

Consta de 150–200 especies, en todos los continentes, mayormente en las regiones templadas; 2 especies en Nicaragua. En Centroamérica se conocen otras 3 especies, naturalizadas de los Estados Unidos y México. Varias especies se utilizan como alimento, como condimento o por sus propiedades medicinales.

Source: [
• 7
]. 

Flowers perfect or rarely unisexual, sessile or subsessile, ebracteate. Sepals (3-) 5, hypogynous, free or basally united, herbaceous, subequal, often strongly 1-ribbed and cucullate. Stamens 5 or fewer, occasionally varying in number in different flowers of the same inflorescence, the flattened filaments free or basally connate, the anthers mostly suborbicular, introrse, dorso-medially attached. Ovary sub- globose, the stigmata 2 (-5), filiform or subulate, mostly sessile or subsessile. Fruit an indehiscent utricle, ovoid to subglobose, the pericarp membranaceous to carnose, free or adherent to the single seed; seeds mostly cochleate-lenticular, smooth to roughened, vertically or horizontally oriented. Annual or perennial often strong- scented herbs. Leaves alternate, entire to pinnatifid, the lowermost at least usually petiolate, frequently glandular or farinose. Inflorescences of terminal or axillary glomerules, the glomerules variously arranged.

Source: [
• 8
]. 

Herbs, annual or perennial [rarely suffruticose, or small trees], farinaceously pubescent with small white inflated hairs or glabrous. Stems erect to prostrate, branched (rarely simple), not jointed, not armed, not fleshy. Leaves alternate, petiolate or sessile, not fleshy; blade linear, oblong, lanceolate, ovate, triangular, trullate, or rhombic, flattened, not jointed, not spinose, base truncate, cordate, hastate, or cuneate, margins entire, dentate, sinuate, or serrate, apex acute to acuminate or obtuse, occasionally lobed. Inflorescences spicate and terminal or axillary glomerules; bracts usually absent or leaflike but narrower than leaves. Flowers bisexual (rarely unisexual, then terminal flower male or bisexual and lateral flowers female), bracteoles absent; perianth segments (3-)5, usually connate at base, sometimes almost to middle or beyond, not imbricate, rounded or keeled abaxially, wings and spines absent; stamens 5 or fewer; ovary superior; style 1 or absent; stigmas 2(-5), filiform. Fruits utricles or achenes, often enclosed in infolded perianth, indehiscent or irregularly dehiscent; pericarp membranaceous or chartaceous, adherent or nonadherent. Seeds horizontal or vertical [rarely oblique], lenticular to subglobose; seed coat black, brown-black, or reddish brown; embryo annular or hippocrepiform (horseshoe-shaped), surrounding copious farinaceous perisperm; radicle inferior or centrifugal. x = 9.

Source: [
• 9
]. 

"Fls perfect (seldom some of them pistillate); cal persistent, mostly 2–5-parted (most commonly 5-, less often 3-), the short, usually blunt segments commonly incurved over the fr (cal only shallowly lobed in one sp.); stamens 1–5, typically isomerous with the cal-lobes; styles 2(–5); fr laterally compressed (the seed erect) or more often flattened across the top (the seed horizontal), thin-walled, the pericarp often adherent to the ± lenticular seed; embryo annular; ours herbs (most spp. annual) with entire or toothed to ± deeply lobed lvs and small, greenish to reddish fls, these in most spp. sessile in glomerules (the glomerules either axillary or in terminal spike-like or panicle-like infls), but in other spp. in compact cymes that may collectively form a thyrse, or otherwise disposed. (Blitum, Roubieva) 100+, cosmop."

Source: [
• 10
]. 

Leaves membranous to more or less fleshy, entire, toothed, or pinnately divided, alternate, mostly petiolate, normally broad.

Source: [
• 4
]. 

Mostly annual or perennial herbs, glabrous, pubescent, glandular or mealy with vesicular hairs.

Source: [
• 4
]. 

Flowers mostly in cymose clusters (“glomerules”) variously arranged but often paniculate and mixed, without bracteoles.

Source: [
• 4
]. 

Stamens 1–5.

Source: [
• 4
]. 

Perianth of both sorts of flower normally (3) 4–5 lobed, unaltered or nearly so in fruit, or sometimes becoming fleshy.

Source: [
• 4
]. 

Fruit with a membranous indehiscent pericarp.

Source: [
• 4
]. 

Stigmas 2 (5).

Source: [
• 4
]. 

Seeds “horizontal” (vertically compressed) or, less commonly, “vertical” (horizontally compressed), testa normally thin, hard and brittle.

Source: [
• 4
]. 

Embryo annular.

Source: [
• 4
]. 

Endosperm present.

Source: [
• 4
]. 

Leaves alternate, mostly petiolate, normally broad

Source: [
• 5
]. 

Mostly annual or perennial herbs, glabrous, pubescent, glandular or mealy with vesicular hairs

Source: [
• 5
]. 

Weeds of cultivated areas and waste lands around human habitations.

Source: [
• 5
]. 

Stamens 1–5

Source: [
• 5
]. 

Calyx of both sorts of flower normally (3–) 4–5-lobed, unaltered or nearly so in fruit, or sometimes becoming fleshy

Source: [
• 5
]. 

Flowers mostly in cymose clusters (“glomerules”) variously arranged, ⚥ and ♀ mixed, without bracteoles

Source: [
• 5
]. 

Endosperm present

Source: [
• 5
]. 

Embryo annular

Source: [
• 5
]. 

Seeds “horizontal” (vertically compressed) or, less commonly, “vertical” (horizontally compressed); testa normally thin, hard and brittle

Source: [
• 5
]. 

Fruits with membranous indehiscent pericarp

Source: [
• 5
]. 

Consisting of about a hundred weedy species, Chenopodiumn is a rather cosmo- politan assemblage of meager economic importance.

Source: [
• 8
]. 

SELECTED REFERENCES

Aellen, P. 1929. Beitrag zur Systematik der Chenopodium-Arten Amerikas. Verwiegend auf Grund der Sammlung des United States National Museum in Washington, D.C. Repert. Spec. Nov. Regni Veg. 26: 31-64, 119-160. Aellen P. and T. Just. 1943. Key and synopsis of the American species of the genus Chenopodium L. Amer. Midl. Naturalist 30: 47-76. Bassett, I. J. and C. W. Crompton. 1982. The genus Chenopodium in Canada. Canad. J. Bot. 60: 586-610. Mosyakin, S. L. 1993. An outline of a system for Chenopodium L. (species of Europe, North and Central Asia). Ukrayins’k. Bot. Zhurn. 50: 71-77. Mosyakin, S. L. and S. E. Clemants. 1996. New infrageneric taxa and combinations in Chenopodium L. (Chenopodiaceae). Novon 6: 398-403. Wahl, H. A. 1954. A preliminary study of the genus Chenopodium in North America. Bartonia 27: 1-46.

Source: [
• 9
].