The families of flowering plants
Habit and leaf form. Herbs. Perennial; with neither basal nor terminal aggregations of leaves; rhizomatous. Stem growth conspicuously sympodial. Hydrophytic to helophytic; rooted. Leaves and stems emergent. Leaves small; whorled; (4–)6–12(–16) per whorl; sessile; simple; epulvinate. Lamina entire; linear; one-veined; without cross-venules. Leaves exstipulate. Lamina margins entire.
Leaf anatomy. Stomata present; on both surfaces. Hairs present. Complex hairs present; peltate.
Lamina isobilateral to centric.
Stem anatomy. Secondary thickening absent (the vascular system reduced to an axile strand of thin-walled tissue, with a narrow zone of phloem outside and a broader region of xylem within). Xylem with vessels, or without vessels (?).
Reproductive type, pollination. Plants hermaphrodite (usually), or monoecious (sometimes, by failure of stamens and pistils to develop in some flowers, then the pistillate flowers occur above the staminate ones), or polygamomonoecious (?). Pollination anemophilous (protogynous).
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences (solitary in the leaf axils); in verticils; small (and inconspicuous). Free hypanthium absent.
Perianth sepaline, or vestigial to absent (greatly reduced, to a more or less entire or 24 lobed rim); 0, or 2–4. Calyx when detectable entire to blunt-lobed.
Androecium 1. Androecial members free of the perianth. Androecium exclusively of fertile stamens. Stamens 1 (borne on top of the ovary); filantherous (the filament slender). Anthers dorsifixed; dehiscing via longitudinal slits; bilocular; tetrasporangiate. Endothecium developing fibrous thickenings. Microsporogenesis simultaneous. Anther wall initially with one middle layer; of the monocot type. Tapetum glandular. Pollen shed as single grains. Pollen grains aperturate; 4–6 aperturate; colpate, or colporate; 3-celled.
Gynoecium ostensibly 1 carpelled. The pistil 1 celled. Gynoecium pseudo monomerous; ostensibly of one carpel; inferior. Carpel stylate (the style often carried between the anther lobes); apically stigmatic (the style stigmatic throughout); 1 ovuled. Placentation apical. Epigynous disk absent. Stigmas dry type; papillate; Group II type (b). Ovules pendulous; non-arillate; anatropous; unitegmic; tenuinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; persistent. Synergids with filiform apparatus. Endosperm formation cellular. Embryogeny onagrad.
Fruit non-fleshy. The fruiting carpel indehiscent; an achene, or drupaceous (the exocarp thin, fleshy). Seeds thinly endospermic. Embryo well differentiated. Cotyledons 2. Embryo straight.
Seedling. Germination phanerocotylar.
Physiology, biochemistry. Not cyanogenic. Alkaloids absent (one species). Iridoids detected; Route II type (+decarb.). Verbascosides detected. Proanthocyanidins absent. Flavonols present; kaempferol (trace). Ellagic acid absent. Saponins/sapogenins absent.
Geography, cytology. Holarctic, Paleotropical, Neotropical, Cape, Australian, and Antarctic. Frigid zone and temperate. Cosmopolitan. X = 8, 16(?).
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgrens Superorder Lamiiflorae; Hippuridales. Cronquists Subclass Asteridae; Callitrichales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; lamiid; Order Lamiales (as a synonym of Plantaginaceae).
Species 1–3. Genera 1; Hippuris.
Illustrations. • Hippuris vulgaris: technical details. • Hippuris vulgaris: technical details (Goebel). • Hippuris vulgaris: Eng. Bot. 516 (1865). • Hippuris vulgaris (B. Ent.).
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. This is much more easily achieved using 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).
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 December 2012. http://delta-intkey.com’.