Plantaginaceae Juss.

Including Littorellaceae S.F. Gray

Habit and leaf form. Herbs (mostly), or shrubs. Plants succulent (e.g. Plantago maritima), or non-succulent. Annual to perennial; with a basal aggregation of leaves, or with neither basal nor terminal aggregations of leaves. Sometimes pachycaul. Helophytic to xerophytic. Heterophyllous, or not heterophyllous. Leaves alternate; spiral; `herbaceous', or leathery, or fleshy (occasionally); petiolate to sessile (the blade/petiole distinction never clear); sheathing. Leaf sheaths not tubular; with free margins. Leaves simple; epulvinate. Lamina entire (usually), or dissected; linear (sometimes ericoid), or lanceolate, or oblanceolate, or ovate, or orbicular; when dissected, more or less pinnatifid; parallel-veined; cross-venulate. Leaves exstipulate.

Leaf anatomy. Hydathodes present (commonly), or absent. Stomata mainly confined to one surface, or on both surfaces; anomocytic, or tetracytic, or diacytic, or cyclocytic.

Lamina dorsiventral, or isobilateral. Minor leaf veins with phloem transfer cells (Littorella, Plantago).

Stem anatomy. Cork cambium present (in rhizomes), or absent; initially deep-seated, or superficial. Nodes unilacunar, or tri-lacunar, or multilacunar. Medullary bundles present, or absent. Secondary thickening absent, or developing from a conventional cambial ring. Xylem with libriform fibres; with vessels. Vessel end-walls simple. Wood partially storied (VI), or not storied; parenchyma absent or extremely sparse.

Reproductive type, pollination. Hermaphrodite, or gynomonoecious, or monoecious. Anemophilous, or anemophilous and entomophilous.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in `inflorescences'; in spikes, or in heads. The terminal inflorescence unit racemose. Inflorescences scapiflorous (at least, pedunculate); terminal; heads or spikes. Flowers bracteate; ebracteolate; small; regular; (3-)4 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk absent.

Perianth with distinct calyx and corolla; (6-)8; 2 whorled; isomerous. Calyx (3-)4 (the posterior sepal seemingly lacking); 1 whorled; gamosepalous, or partially gamosepalous. When ostensibly only partially gamosepalous, 2 of the members joined (the abaxial pair). Calyx regular (diagonal); persistent; imbricate. Corolla (3-)4 (the two posterior petals fused?); 1 whorled; gamopetalous; imbricate (membranous); regular, or unequal but not bilabiate (the lobes unequal in Bougueria).

Androecium (1-)4. Androecial members adnate (to the corolla); all equal; free of one another; 1 - whorled. Androecium exclusively of fertile stamens. Stamens (1-)4; reduced in number relative to the adjacent perianth to isomerous with the perianth; oppositisepalous. Anthers dorsifixed; versatile; dehiscing via longitudinal slits; introrse. Microsporogenesis simultaneous. Tapetum glandular. Pollen grains aperturate; (3-)4-14 - aperturate; porate (occasionally), or foraminate; 2-celled, or 3-celled.

Gynoecium 2. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary 2 locular. Gynoecium median; stylate. Styles 1; attenuate from the ovary; apical. Stigmas usually 2 - lobed; dry type; non-papillate; Group II type. Placentation axile (Plantago), or basal. Ovules 5-50 per locule (i.e. to many, in Plantago), or 1 per locule; peltate; non-arillate; hemianatropous, or anatropous, or campylotropous; unitegmic; tenuinucellate. Endothelium differentiated. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; persistent. Synergids pear-shaped. Endosperm formation cellular. Endosperm haustoria present; chalazal and micropylar (aggressive). Embryogeny onagrad.

Fruit non-fleshy; dehiscent, or indehiscent; a capsule (membranous), or a nut. Capsules circumscissile. Seeds copiously endospermic. Cotyledons 2. Embryo achlorophyllous (6 species of Plantago); straight (usually), or curved.

Seedling. Germination phanerocotylar.

Physiology, biochemistry. Not cyanogenic. Alkaloids present, or absent. Iridoids recorded; carbocyclic and seco-compounds. Proanthocyanidins absent. Ellagic acid absent (4 species of Plantago). Arbutin absent. Ursolic acid present. Saponins/sapogenins present, or absent. Aluminium accumulation not found. C3. C3 recorded in Plantago. Anatomy non-C4 type (Plantago).

Geography, cytology. Frigid zone to tropical. Cosmopolitan. X = 4-12(+).

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren's Superorder Lamiiflorae; Scrophulariales. Cronquist's Subclass Asteridae; Plantaginales. Takhtajan's Subclass Asteridae; Lamianae; Scrophulariales. Species 270. Genera 3; Bougueria, Littorella, Plantago.

Economic uses, etc. Widespread weeds, and a laxative from P. psyllium seed.

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