The genus was originally described to include one (later two) species of subtribe Helianthinae that were characterized by having pales that tightly enclosed the cypselae (achenes) (see Feddema, 1971).

[1] Aldama is currently, characterized by having a perennial herbaceous habit, a pappus usually of awns and scales, and a multi-seriate involucre.

Botanists Schilling & Panero in 2002 and 2011, studied the subtribe Helianthinae based on molecular sequences of nuclear ITS, ETS, and cpDNA, coming to a conclusion that the genus Viguiera Kunth, did not constitute a monophyletic group.

Among their conclusions they proposed to reclassify the genus, dividing and relocating its species in at least eleven genera: Aldama La Llave, Bahiopsis Kellogg, Calanticaria (B.L.

[4][5] It is native to (countries of): Argentina, Belize, Bolivia, Brazil, northern and central Chile, Ecuador, Guatemala, Honduras, Mexico, Nicaragua, Paraguay, Peru, Uruguay, United States (in the states of Arizona, New Mexico and Texas) and Venezuela.