Chenopodium: Answers to key questions in Budd's Flora and Flora of Alberta leading to this genus.  Not all the answers apply to all the species in Chenopodium, but they all do apply to simplex.   

	herbs, or low spineless shrubs; NOT [shrub with spiny branches, 1-2 m high]
	plants not prickly; NOT [plant prickly from the spine-tipped thread-like leaves and from bracts]
	stems not fleshy
	stems not jointed
	leaves mostly alternate; NOT [leaves opposite]
	leaves not reduced to scales
	leaves not circular in cross section
	NOT [flowers axillary and sunk into the fleshy stem]
	flowers not subtended by scarious bracts
	flowers lacking bracteoles; NOT [pistillate flowers with a pair of bracteoles, occasionally 3]
	calyx with 3-5 sepals; NOT [calyx with only one sepal]
	sepals greenish, herbaceous or fleshy; NOT [sepals scarious, dry and membranous]
	mature calyx without wings or spines; NOT [mature calyx with wings, or minute spines]
	flowers perfect
	at least some flowers with more than one stamen
	fruit enclosed; NOT [fruit largely exposed]
	fruit not winged; NOT [fruit narrowly winged]

Amaranthaceae: Answers to key questions in Budd's Flora leading to this family.  Not all the answers apply to all the genera in Amaranthaceae, but they all do apply to Chenopodium. 

	herbs; NOT [shrubs or trees]
	land plants; NOT [water plants]
	plants not parasitic on trees, rooted in soil
	plants with more than one pair of leaves
	leaves alternate, lower ones sometimes opposite; NOT [leaves opposite]
	leaves without stipules; NOT [leaves with stipules free or sheathing the stem]
	leaves not compound and not very deeply divided; NOT [leaves compound or simple, but very deeply divided]
	leaves not orbicular or reniform; NOT [leaves orbicular or reniform]
	flowers small, numerous, greenish; NOT [flowers colored]
	flowers with only one floral ring, with sepals but not petals
	perianth segments 2-5; NOT [perianth segments 6]
	flowers perfect
	fruit dry when ripe; NOT [fruit fleshy when ripe]