Boraginoideae

Some taxonomists placed the genera Codon and Wellstedia in Boraginoideae. Others place one or both of these in separate, monogeneric subfamilies. Codon was long regarded as an odd member of Hydrophylloideae, but in 1998, a molecular phylogenetic study suggested that it is closer to Boraginoideae.^[1] Neither is included n more modern classifications.^[2]

Some authors proposed a revision of earlier APG systems, in which Boraginaceae had been included as an unplaced family (i.e. not included in a specified order) within the lamiid clade of eudicots. In that system. Boraginaceae was defined broadly (Boraginaceae sensu lato or s.l.). Instead they proposed recognizing five to eight families in a separate order, the Boraginales.^[3][2] In that system Boraginaceae is treated in a narrow sense (sensu stricto or s.s.). Subsequently the order Boraginales was added to the 2016 revision (APG IV) to include Boraginaceae at the ordinal level, in which it was the sole family. The consensus was to continue the broad usage rather than split it into separate families, based on its monophyletic composition.^[4] The subfamilial structure applies solely to Boraginaceae s.s., which includes around 1,600 to 1,700 species divided into some 90 genera.^{[citation needed]}

Comparisons of DNA sequences by cladistic methods suggested the division of Boraginoideae into four tribes: Echiochileae, Boragineae, Lithospermeae, and Cynoglosseae.^[5] This was subsequently resolved into only two tribes, Boragineae and Lithospermeae (25 genera). Boragineae was then further subdivided into two subtribes, Boragininae (15 genera) and Moritziinae (2).^[2]

Genera and approximate number of species in the system of Chacon et al (2016):^[2]

• Tribe Boragineae
• Subtribe Boragininae (140 species)

Anchusa, Anchusella, Borago, Brunnera, Cynoglottis, Gastrocotyle, Hormuzakia, Lycopsis, Melanortocarya, Nonea, Pentaglottis, Phyllocara, Pulmonaria, Symphytum, Trachystemon

• Subtribe Moritziinae (6 species)

Moritzia, Thaumatocaryon

• Tribe Lithospermeae (460 species)

Aegonychon, Alkanna, Ancistrocarya, Arnebia, Buglossoides, Cerinthe, Cystostemon, Echiostachys, Echium, Glandora, Halacsya, Huynhia, Lithodora, Lithospermum, Lobostemon, Maharanga, Mairetis, Moltkia, Moltkiopsis, Neatostema, Onosma, Paramoltkia, Podonosma, Pontechium, Stenosolenium.^[6]

The following list of genera consists of Codon plus the genera listed for Boraginoideae at the Germplasm Resources Information Network^[7]