Herbs annual, erect, glabrous. Leaves alternate, petiolate; leaf blade flattened, triangular-ovate or hastate, margin entire or lobed-serrate. Flowers unisexual (plants dioecious), forming glomerules, male ones usually arranged in terminal, interrupted panicles, female ones axillary. Male flowers: perianth 4- or 5-parted; segments oblong, apex obtuse; stamens 4 or 5, inserted at base of perianth; filaments capillary; anthers exserted. Female flowers borne within 2 united, leathery, and hardening bractlets; perianth absent; ovary subglabrous; ovule subsessile; stigmas 4 or 5, filiform. Utricle compressed globose; pericarp membranous, adnate to seed. Seed vertical; embryo annular; perisperm copious, farinaceous.
Herbs, annual or biennial, monoecious, glabrous. Stems erect, not branched, not jointed, not armed, not fleshy. Leaves basal or alternate, petiolate; blade triangular-hastate to ovate, sometimes with elongated lobes, margins entire or dentate, apex acute. Inflorescences: pistillate flowers sessile in leaf axils; staminate flowers in dense terminal spikes. Flowers unisexual, rarely bisexual; staminate flowers with perianth segments 4-5, stamens 4-5; pistillate flowers enclosed by 2 accrescent or connate bracts, perianth absent, stigmas 4-5. Fruiting structures enlarged and hardened bracteoles enclosing achenes; pericarp adherent. Seeds vertical, seed coat dark, spiny or smooth; hardened bracteoles serving as seed coat; embryo annular; perisperm copious. x = 6.
|Spinach [Latin spina, spine, in reference to spiny fruit, or Persian ispanakh, spinach]|