The families of flowering plants
Including Pongatieae (Pongatiaceae) Endl.
Habit and leaf form. Herbs; non-laticiferous and without coloured juice. Plants having stems more or less succulent. Annual. Helophytic. Leaves alternate; spiral; non-sheathing; simple. Lamina entire; pinnately veined. Leaves exstipulate.
General anatomy. Plants with laticifers (perhaps, in the phloem), or without laticifers (?).
Leaf anatomy. The leaf lamina dorsiventral. Stomata tetracytic. The mesophyll containing crystals. The crystals druses.
Axial (stem, wood) anatomy. Young stems with hollow internodes. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring.
The vessel end-walls simple. Included phloem absent.
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in spikes. The ultimate inflorescence units racemose. Inflorescences terminal; dense spikes. Flowers bracteate; bracteolate (two bracteoles); small; regular; 5 merous; cyclic; tetracyclic. Free hypanthium absent.
Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; gamosepalous; regular; persistent; imbricate. Corolla 5; 1 whorled; gamopetalous; imbricate; campanulate, or urceolate; regular.
Androecium 5. Androecial members adnate (to the corolla); free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 5; isomerous with the perianth; oppositisepalous; alternating with the corolla members; filantherous (the filaments short). Anthers dehiscing via longitudinal slits; introrse. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral (usually), or isobilateral (rarely). Anther wall initially with one middle layer (?). Tapetum glandular. Pollen grains aperturate; 3 aperturate; colporate (to colporoidate); 3-celled.
Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth. The pistil 2 celled. Gynoecium syncarpous; eu-syncarpous; partly inferior to inferior. Ovary 2 locular. Styles 1; apical. Stigmas 1; capitate. Placentation axile (the placentas stipitate). Ovules 10–50 per locule (many); non-arillate; anatropous; unitegmic; tenuinucellate. Endothelium differentiated. Embryo-sac development Polygonum-type. Endosperm formation cellular. Embryogeny onagrad.
Fruit non-fleshy; dehiscent; a capsule. Capsules circumscissile. Fruit 15–100 seeded (many). Seeds more or less non-endospermic; minute. Cotyledons 2. Embryo straight.
Seedling. Germination phanerocotylar.
Physiology, phytochemistry. Aluminium accumulation not found.
Special distinguishing feature. Lamina tip not abaxially pouched (i.e., not as in Saccifoliaceae).
Geography, cytology. Tropical. Pantropical. N = 12.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgrens Superorder Asteriflorae; Campanulales. Cronquists Subclass Asteridae; Campanulales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; lamiid; Order Solanales.
Species 2. Genera 1; only genus, Sphenoclea.
Illustrations. • Sphenoclea zeylanica: Nat. Pflanzenfam. IV (1894). • Sphenoclea pongatium: R. Wight 2 (1850).
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: 22nd July 2014. http://delta-intkey.com’.