Amaranthaceae

Picture 1 Distribution of Amaranthaceae (Mobot.org)

Mostly herbs, seldom climbers, subshrubs, shrubs, or even (rarely) small trees, commonly with animalous secondary growth resulting in the formation of concentric rings of vascular bundles; plants often accumulating free oxalates, potassium nitrate and saponins, producing betalains but not anthocyanins, not tanniferous, lacking both proanthocynins and ellagic acid; nodes unilavunar; crystals of calcium oxalate commonly present in some of the cells of the parenchymatous tissues, often as clustered crystals or crystals sand; vessel-segments with simple perforations; imperforate tracheary elements with simple pits; sievetubes with a special kind o p-type plastid that includes a subperipheral ring of proteinaceous filaments, but without a central protein crystaloid.

Leaves. Alternate or opposite, simple and commonly entire or nearly so often with Kranz anatomy, the vascular bundles surrounded by large, cubical parenchyma cells, stoamates variously anomacytic, anidocytic, diacytic or paracytic.

Flowers small, solitary or more often in cymose or variously compound inflorescens, often subtended bt scarious or membranous bracts or bracteoles, variously entomorphilous or anemophilous, generally regular, perfect or less often unixeual, hypogynous or nearly so, apetalouus; sterile flowers, forming hooks or bristles, often presents, subtending nornal flowers; sepals mostly 3-5, seldom only 1 or 2 or even wanting, stamens generally as many as the sepals and opposite them, filaments istinct or more often connate at the base into a tube, the tube often produced into teeth or lobes (“pseudostaminodia”). sympetalous corolla with the filaments attached at the sinuses, usually trinucleate; a nectary-ring often present at the inner base of the filament-tube; gynoecium of 2-3 carpels united to form a compound, unicular ovary with a single, ovules usually solitary and basal (rarely apical and pendulous), free-central placenta; bitegmic.

Fruit. An achene or a small nut, or vcircumscissile, 1-seeded capsule, rarely a berry, often subtended or more or less enclosed bye the persistent calyx, seeds with peripheral, annular, dicotyledonous embryo, hard to granular perisperm, true endosperm nearly or quite wanting (Cronquist, 1981)