Individual flowers have six blue to purple tepals, joined at the base to form a tube with free lobes at the mouth.

The size and shape of the staminodes and of the structures at the base of the filaments are important diagnostic characters.

Specimens of what is now called Brodiaea were first collected by Archibald Menzies, botanist to the Vancouver Expedition, in 1792.

This was in James Edward Smith's 1807 An introduction to physiological and systematical botany, where Smith used it to argue that the tepals of liliaceous plants are sepals rather than petals: "I cannot conceal a recent discovery which strongly confirms the opinion of my acute and candid friend.

Two species of a new genus, found by Mr. Menzies on the West coast of North America, have beautiful liliaceous flowers like an Agapanthus, with six internal petals besides!

George Boulger, writing in the Dictionary of National Biography, says that Smith's actions were deliberately intended to deprive Salisbury of credit for the genus.

[16] Brodiaea belongs to a group of 12 genera whose affinities were the subject of much controversy until the end of the 20th century.

Others placed this group at lower taxonomic rank and usually included them in Liliaceae, Alliaceae, or Amaryllidaceae.

Molecular phylogenetic studies confirmed the suspicions of many that this group was misplaced, and consequently, the family Themidaceae was resurrected in 1996.

When the APG III system was published in 2009, the former Themidaceae was treated as a subfamily, Brodiaeoideae, of the family Asparagaceae sensu lato.

[23] As of September 2013[update], the World Checklist of Selected Plant Families lists the following 17 species.