The taxonomy presented here is a modified form of the Porter & Johnson (2000) classification. I have adopted this scheme because it bases the recognition of higher taxa (e.g., genera and sections) on inferences of monophyly. The modifications represented here are based upon studies of phylogenetic relationships published subsequent to the Porter & Johnson classification. See also the Tree of Life webpages.
The web pages are organized hierarchically. The first-order of the hierarchy is represented by the three subfamilies (described below).
Gen. pl., p. 136, 1789. Cobeaceae D. Don, Edinburgh Philos. J. 10: 109, 1824.
Vines (Cobaea), trees (Cantua), shrubs, perennial, biennial, or annual herbs; roots variable, taprooted or with branched root systems, sometimes rhizomatous, some species rooting at the nodes. Stems erect to decumbent, scandant or sprawling Flowers typically of five sepals, five fused petals, and five epipetalous or basally adnate stamens (but perianth and androecium consistently 4- or 6-merous in some Linanthus). Superior ovary of three fused and loculicidally dehiscing carpels (bicarpellate in some Navarettia; septacidal in Cobaea, sometimes both loculicidal and septicidal in Acanthogilia). Petals convolute in aestivation (imbricate in some Cantua). Annular nectary disk nearly always present present (absent in Cantua dendritica and C. flexuosa); ovules unitegmic and tenuinucellate; endosperm development nuclear. (Phylogenetic definition—The least incorporative monophyletic group of species that contains Acanthogilia gloriosa, Bonplandia geminiflora, Cantua buxifolia, Cobaea scandens, Gilia laciniata, Loeselia ciliata, Phlox glaberrima, and Polemonium caeruleum.) Type: Polemonium L.
Generic membership.—Acanthogilia, Aliciella, Allophyllum, Bonplandia, Bryantiella, Cantua, Cobaea, Collomia, Dayia, Eriastrum, Gilia, Giliastrum, Gymnosteris, Ipomopsis, Langloisia, Lathrocasis, Leptosiphon, Linanthus, Loeselia, Loeseliastrum, Microgilia, Microsteris, Navarretia, Phlox, Polemonium, and Saltugilia (3 subfamilies, 26 genera, ~379 species).
Polemoniaceae are composed of three primary lineages, here treated as subfamilies: Acanthogilioideae, Cobaeoideae, and Polemonioideae. The relationships among these three lineages remain debated (compare Johnson et al 1996, Porter 1997, Porter and Johnson 1998, Grant 1998, Prather et al. 2000, Grant 2004, Johnson et al 2008 and Porter et al 2010). Every possible combination has been proposed and every hypothesis has some degree of support. While there is no question that these represent the three earliest diverging lineages of the family, it remains a mystery which two of them shares more recent common ancestry.
Key to the Subfamilies of Polemoniaceae:
1. Primary leaves (leaves of long shoots) once-pinnatifid, becoming persistent pinnate spines, axillary leaves (leaves of short shoots) linear and wholly herbaceous...Acanthogilioideae
1. Primary leaves simple, toothed, lobed, once-, twice-pinnatifid, palmatifid, never becoming persistent pinnate spines, axillary leaves, if present, various and herbaceous...2
2. Trees, large shrubs (more that 1 meter in height), or vines of tropical or subtropical distribution...Cobaeoideae
2. Annuals, herbaceous perennials, sub-shrubs, small shrubs (less than 1 meter in height) of boreal, temperate or subtropical distribution (rarely tropical)...Polemonioideae
ACANTHOGILIOIDEAE J. M. Porter & L. A. Johnson
Aliso 19: 60, 2000.
Shrubs with persistent, alternate, spiny, pinnately lobed primary leaves and deciduous, linear secondary leaves that are axillary and fascicled on short shoots. Calyx and corolla radially symmetric, corolla salverform. Fruits dehiscing only about half the length, either loculicidal or both loculicidal and septicidal. Seeds winged. (Phylogenetic definition—The monophyletic group descended from the first ancestor of Acanthogilia gloriosa to evolve persistent, spinescent primary leaves, formed by the lignification of the vascular bundles of the leaf, and simultaneously zonocolporate pollen bearing verruca.) Type: Acanthogilia A. G. Day & Moran.
Generic membership.—Acanthogilia (1 species).
Cobaeoideae (D. Don) Arn.
Encycl. Brittanica ed. 7 v.5, p.121, 1832. Cobeaceae D. Don, Edinburgh Philos. J. 10: 109, 1824.)
Vines, trees, shrubs, or rarely herbs. Leaves alternate, simple and entire to pinnately lobed or compound. Calyx lobes nearly free (e.g., Cobaea) or fused, wholly herbaceous or hyaline between vasculature (e.g., Cantua). Corolla campanulate to tubular or salverform, medium to large, with epipetalous stamens inserted at corolla base or on tube. Seeds narrowly to broadly winged, rarely wingless (Bonplandia). (Phylogenetic definition—The least incorporative monophyletic group of species that includes Bonplandia geminiflora, Cantua buxifolia, and Cobaea scandens.) Type: Cobaea Cav.
Generic membership.— Bonplandia, Cantua, and Cobaea (three tribes, three genera, ~33 species).
Polemonioideae (Juss.) Arn.
Encycl. Brittanica ed. 7, v.5, p.121, 1832.
Annual, biennial, or perennial herbs, or shrubs. Leaves opposite or alternate, linear and entire to variously pinnately or palmately lobed, or pinnately or palmately compound. Flowers rotate, campanulate, tubular, funnelform or salverform, radially or occasionally bilaterally symmetric. Seeds generally without wings, but occasionally with narrow wings (e.g., some species of Aliciella, Loeselia, and Polemonium). (Phylogenetic definition—The least incorporative monophyletic group of species that includes Gilia laciniata, Loeselia ciliata, Phlox glaberrima, and Polemonium caeruleum.) Type: Polemonium L.
Generic membership.—Aliciella, Allophyllum, Bryantiella, Collomia, Dayia, Eriastrum, Gilia, Giliastrum, Gymnosteris, Ipomopsis, Langloisia, Lathrocasis, Leptosiphon, Linanthus, Loeselia, Loeseliastrum, Microgilia, Microsteris, Navarretia, Phlox, Polemonium, and Saltugilia (four tribes; 22 genera; ~330 species).