The families of flowering plants
Including Pinguiculariaceae Dum., Utriculinae (Utriculariaceae) Hoffmgg. & Link
Habit and leaf form. Herbs. Normal plants, or switch-plants, or plants of very peculiar vegetative form; Utricularia often exhibiting no clear distinction between stems, roots and leaves, the stem bearing photosynthetic appendages equipped with animal-trapping bladders. Leaves well developed, or absent (in some Utricularia species). Plants with roots, or rootless (floating Utricularia species); carnivorous. Trapping mechanism active, or passive. The traps in the form of minute (submerged) bladders (Utricularia, Polypompholyx), or constituted by sticky leaf glands, associated with subsequent, slow enclosure of the prey by movement of the blade (Pinguicula), or consisting of pitchers (Genlisea). Perennial; with a basal aggregation of leaves, or without conspicuous aggregations of leaves. When rooted/non-aquatic, self supporting, or epiphytic. Hydrophytic, or helophytic; when aquatic, free floating, or rooted. Leaves of hydrophytes submerged, or emergent. Heterophyllous (often, with both modified and normal leaves), or not heterophyllous. Leaves alternate; spiral; when identifiable herbaceous; petiolate, or subsessile; non-sheathing; when identifiable simple. Lamina entire; pinnately veined. Leaves exstipulate; leaf development not graminaceous.
Leaf anatomy. Stomata present, or absent (from foliage leaves of Genlisea); mainly confined to one surface, or on both surfaces; diacytic (mostly, in Pinguicula), or anomocytic (at least sometimes, in Utricularia). Hairs present; mostly capitate and glandular. Minor leaf veins without phloem transfer cells (Pinguicula, Lentibularia).
Axial (stem, wood) anatomy. Nodes with one leaf trace. Primary vascular tissues comprising a ring of bundles (in Pinguicula scapes), or in a cylinder, without separate bundles (in that instead of typical vascular bundles, the axes in other genera either exhibit a network of phloem strands which is separated by parenchyma from an independent ring of xylem around the pith, or have alternate strands of xylem and phloem attached to a ring of sclerenchyma). Secondary thickening absent.
Reproductive type, pollination. Plants hermaphrodite. Pollination entomophilous.
Inflorescence, floral, fruit and seed morphology. Flowers solitary (sometimes), or aggregated in inflorescences; when aggregated, in racemes and in spikes. The ultimate inflorescence units racemose. Inflorescences scapiflorous. Flowers bracteate, or ebracteate; small to medium-sized; very irregular; zygomorphic. The floral irregularity involving the perianth and involving the androecium. Flowers basically 5 merous; cyclic; tetracyclic, or pentacyclic. Free hypanthium absent. Hypogynous disk absent.
Perianth with distinct calyx and corolla; 4–10; 2 whorled, or 3 whorled; isomerous, or anisomerous. Calyx 2, or 4–5 (lobed); 1 whorled, or 2 whorled (Polypompholyx); gamosepalous; blunt-lobed; bilabiate (often), or unequal but not bilabiate; persistent; imbricate, or open in bud; at least theoretically with the median member posterior. Corolla 5 (at least theoretically), or 2 (sometimes, ostensibly); 1 whorled; gamopetalous; imbricate; bilabiate (the upper, posterior lip of two joined members, the lower of three and commonly personate); spurred (or saccate, anteriorly).
Androecium 2, or 4. Androecial members adnate; free of one another; 1 whorled. Androecium exclusively of fertile stamens, or including staminodes. Staminodes if present, 2 (posterior); in the same series as the fertile stamens; representing the posterior-lateral pair. Fertile stamens representing the anterior-lateral pair. Stamens 2 (the anterior pair); inserted near the base of the corolla tube; reduced in number relative to the adjacent perianth; more or less theoretically oppositisepalous; alternating with the corolla members. Anthers connivent; dorsifixed; dehiscing via longitudinal slits; unilocular, or unilocular to bilocular (transversely constricted); tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with one middle layer. Tapetum glandular. Pollen grains aperturate; 3–16 aperturate; colporate (sometimes syncolpate, sometimes zonorate); 3-celled (in Utricularia).
Gynoecium 2 carpelled (the posterior member represented by its reduced stigma). Carpels reduced in number relative to the perianth. The pistil 1 celled. Gynoecium syncarpous; synstylovarious; superior. Ovary 1 locular. Gynoecium median (the stigmas one posterior, the other anterior). Ovary sessile. Gynoecium non-stylate, or stylate. Styles 1; apical. Stigmas 1–2 (the posterior lobe more or less abortive); wet type; papillate; Group III type. Placentation free central. Ovules in the single cavity (2–)5–100 (i.e. to many); funicled (?), or sessile, or sunken in the placenta (often); non-arillate; anatropous; unitegmic; tenuinucellate. Endothelium differentiated. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization (usually), or fusing simultaneously with the male gamete (Pinguicula vulgaris). Antipodal cells formed; 3; not proliferating; ephemeral, or persistent (small or large, sometimes the upper becoming much enlarged while the other two degenerate). Endosperm formation cellular. Endosperm haustoria present; chalazal and micropylar (aggressive). Embryogeny onagrad, or asterad, or chenopodiad.
Fruit non-fleshy; dehiscent, or indehiscent; a capsule, or capsular-indehiscent (?). Capsules valvular (24 valves), or circumscissile, or splitting irregularly. Seeds non-endospermic. Embryo rudimentary at the time of seed release. Embryo chlorophyllous (1/1); straight.
Seedling. Germination phanerocotylar.
Physiology, phytochemistry. Anatomy non-C4 type (Utricularia). Not cyanogenic. Alkaloids present, or absent. Iridoids detected; Route II type (normal and decarb.). Saponins/sapogenins absent. Proanthocyanidins absent. Flavonols absent. Ellagic acid absent (2 genera, 2 species). Aluminium accumulation demonstrated (in Utricularia).
Geography, cytology. Frigid zone to tropical. Cosmopolitan. X = 6, 8, 9, 11, 21.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgrens Superorder Lamiiflorae; Scrophulariales. Cronquists Subclass Asteridae; Scrophulariales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; lamiid; Order Lamiales.
Species 245. Genera 3, or 4; Genlisea, Pinguicula, Polypompholyx (= Utricularia), Utricularia.
General remarks. For discussion of classificatory problems posed by Scrophulariaceae, impinging on Bignoniaceae, Buddlejaceae, Callitrichaceae, Plantaginaceae, Hippuridaceae, Lentibulariaceae, and Hydrostachydaceae, and such problem genera as Paulownia and Schlegelia, see Olmstead and Reeves (1995), who provide preliminary insights from chloroplast gene sequencing.
Illustrations. • Technical details: Utricularia. • Technical details: Utricularia (Thonner). • Technical details: Pinguicula. • Pinguicula alpina: Eng. Bot. 1123, 1867. • Pinguicula grandiflora: Eng. Bot. 1122, 1867. • Pinguicula lusitanica: Eng. Bot. 1124, 1867. • Pinguicula vulgaris: Eng. Bot. 1121, 1867. • British Pinguicula spp. (B. Ent. compilation). • Utricularia australis: as U. neglecta, Eng. Bot. 1125bis, 1867. • Utricularia intermedia: Eng. Bot. 1127, 1867. • Utricularia minor: Eng. Bot. 1126, 1867. • Utricularia vulgaris: Eng. Bot. 1125, 1867. • British Utricularia spp. (B. Ent. compilation). • Utricularia menziesii (photo). • Utricularia montana (TS inflorescence axis) and U. minor (TS of the axile vascular strand): Solereder, 1908. • Bladders of Utricularia flexuosa, U. minor, U. neglecta, U. montana: anatomical details (Solereder, 1908).
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: 19th October 2016. delta-intkey.com’.