matricaria: chiefly Old World strong-smelling weedy herbs; comprises plants sometimes included in other genera: e.g. Tanacetum; Tripleurospermum
dicot genus: genus of flowering plants having two cotyledons (embryonic leaves) in the seed which usually appear at germination
stoichiometry: (chemistry) the relation between the quantities of substances that take part in a reaction or form a compound (typically a ratio of whole integers)