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The families of flowering plants

L. Watson and M.J. Dallwitz

Polemoniaceae Juss.

Excluding Cobaeaceae.

Habit and leaf form. Herbs, or shrubs (sometimes), or trees (Cantua). Annual to perennial; without conspicuous aggregations of leaves. Leaves alternate, or opposite, or whorled (Gymnosteris); when alternate, spiral; petiolate to sessile; simple, or compound; when compound pinnate, or palmate. Lamina when simple, dissected, or entire; pinnatifid, or palmatifid; cross-venulate. Leaves exstipulate. Lamina margins entire, or serrate, or dentate.

Leaf anatomy. The leaf lamina dorsiventral, or bifacial (then isobilateral). Mucilaginous epidermis present, or absent. Stomata present; mainly confined to one surface (abaxial), or on both surfaces (usually, especially in species with narrow leaves); anomocytic, or paracytic (also associated with narrow leaves). Hairs present; eglandular (mostly uniseriate, curved or straight, sometimes woolly), or glandular (then generally with uniseriate stalk and unicellular or multicellular head); mostly multicellular. Multicellular hairs simple (usually), or branched (occasionally with lateral protrusions). Adaxial hypodermis present (then confined to leaf margins and/or over the median vein), or absent. Lamina without secretory cavities. Minor leaf veins without phloem transfer cells (Phlox, Polemonium).

Axial (stem, wood) anatomy. Cork cambium present; initially deep-seated, or initially superficial. Nodes unilacunar. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. The anomalous secondary thickening generally absent.

The vessel end-walls simple, or scalariform and simple (with few cross bars). The vessels without vestured pits. The axial xylem with tracheids, or without tracheids (?); with libriform fibres. ‘Included’ phloem absent. The wood partially storied (VPI), or not storied (?).

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers solitary (sometimes), or aggregated in ‘inflorescences’; when aggregated, in cymes, or in heads, or in corymbs. The ultimate inflorescence units cymose. Inflorescences cymes or corymbs, sometimes condensed into heads; with involucral bracts, or without involucral bracts; pseudanthial, or not pseudanthial. Flowers bracteolate, or ebracteolate; regular (usually), or somewhat irregular; when irregular, slightly zygomorphic (then slightly bilabiate); 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal; of separate members, or annular.

Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; gamosepalous; five blunt-lobed; bilabiate to regular; persistent; imbricate, or valvate. Corolla 5; 1 whorled; gamopetalous; usually contorted; campanulate, or funnel-shaped, or hypocrateriform; bilabiate to regular.

Androecium 5. Androecial members adnate (epipetalous); free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 5; inserted near the base of the corolla tube, or midway down the corolla tube, or in the throat of the corolla tube; isomerous with the perianth; oppositisepalous; alternating with the corolla members. Anthers dehiscing via longitudinal slits; tetrasporangiate. Endothecium developing fibrous thickenings. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral. Anther wall initially with one middle layer; of the ‘dicot’ type. Pollen grains aperturate; 7–32 aperturate; porate, or colporate (colpoidorate?), or foraminate; 2-celled (in Gilia and Phlox).

Gynoecium (2–)3(–5) carpelled. Carpels reduced in number relative to the perianth, or isomerous with the perianth. The pistil (2–)3(–5) celled. Gynoecium syncarpous; synstylovarious; superior. Ovary (2–)3(–5) locular. Gynoecium median. Ovary sessile. Gynoecium stylate. Styles 1 (filiform). Stigmas (2–)3(–5); (2–)3(–5) lobed. Placentation axile. Ovules 1–50 per locule (to ‘many’); sessile; apotropous; anatropous; unitegmic; tenuinucellate. Endothelium differentiated. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids pear-shaped. Endosperm formation nuclear. Embryogeny chenopodiad.

Fruit non-fleshy; dehiscent (usually), or indehiscent; a capsule (usually), or capsular-indehiscent. Capsules when dehiscent, loculicidal. Seeds endospermic. Endosperm oily. Cotyledons 2. Embryo chlorophyllous (2/3), or achlorophyllous (3 species of Polemonium); slightly curved, or straight.

Seedling. Germination phanerocotylar.

Physiology, phytochemistry. C3. C3 physiology recorded directly in Cantua, Gilia, Phlox, Polemonium. Not cyanogenic. Alkaloids absent (6 species). Iridoids not detected. Saponins/sapogenins present. Proanthocyanidins absent. Flavonols present; kaempferol, or kaempferol and quercetin. Ellagic acid absent (2 genera, 2 species). Aluminium accumulation not found.

Geography, cytology. Holarctic and Neotropical. Frigid zone to sub-tropical. Widespread, but lacking (though often introduced) in Africa, Southern and Southeast Asia Malaysia, Australia and Eastern South America. X = 6, 7, 8, 9. Supposed basic chromosome number of family: 9.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Solaniflorae; Solanales. Cronquist’s Subclass Asteridae; Solanales. APG III core angiosperms; core eudicot; Superorder Asteranae. APG IV Order Ericales.

Species 300. Genera 18; Acanthogilia, Allophyllum, Bonplandia, Cantua, Collomia, Eriastrum, Gilia, Gymnosteris, Huthia, Ipomopsis, Langloisia, Leptodactylon, Linanthus, Loeselia, Loeseliastrum, Navarretia, Phlox, Polemonium.

Illustrations. • Le Maout and Decaisne: Polemonium. • Gilia achilleifolia: as G. achilleaefolia, Bot. Reg. 1682, 1835. • Gilia androsacea: as Leptosiphon androsaceus, Bot. Reg. 1710, 1835. • Phlox drummondii: Bot. Reg. 1949, 1837. • Polemonium caeruleum: Eng. Bot. 922 (1866). • Polemonium caeruleum var. piliferum: Bot. Reg. 1303, 1829. • Polemonium lanatum, var.: Bot. Reg. 1304, 1829.

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 15th April 2018.’.