The families of flowering plants
Including Modeccaceae J.G. Agardh, Paropsiaceae Dum.; excluding Malesherbiaceae, Turneraceae.
Habit and leaf form. Trees and shrubs, or lianas (and herbaceous climbers). Self supporting, or climbing; the climbers tendril climbers (the tendrils axillary, perhaps representing modified inflorescences). Mesophytic, or xerophytic. Leaves alternate; spiral; petiolate; non-sheathing; simple, or compound (e.g. in Deidamia, Passiflora); when compound, palmate. Lamina when simple dissected, or entire; when dissected, palmatifid; pinnately veined, or palmately veined; cross-venulate. Leaves stipulate, or exstipulate. Stipules when present, free of one another; usually small, caducous. Leaf development not graminaceous.
Leaf anatomy. The leaf lamina dorsiventral (usually), or bifacial (then isobilateral). Extra-floral nectaries commonly present (on the petioles). Mucilaginous epidermis present, or absent. Stomata usually mainly confined to one surface (abaxial); anomocytic. Hairs present (representing diverse types - unicellular, uniseriate, tufted, shaggy, eglandular and glandular). Adaxial hypodermis present (occasionally), or absent. Lamina with secretory cavities (e.g., in Adenia, containing tannin), or without secretory cavities (but tanniniferous cells common). The mesophyll with sclerenchymatous idioblasts (occasionally), or without sclerenchymatous idioblasts; containing crystals. The crystals raphides and solitary-prismatic. Minor leaf veins without phloem transfer cells (Passiflora).
Axial (stem, wood) anatomy. Secretory cavities present (e.g., in Adenia, containing tannin), or absent (but tanniniferous cells common). Cork cambium present; initially superficial. Nodes tri-lacunar. 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, or anomalous (rarely). The anomalous secondary thickening in Adesmia, via concentric cambia. Primary medullary rays wide, or mixed wide and narrow, or narrow.
The wood semi-ring porous to diffuse porous. The vessels very variable in size, small to large; variously solitary, or radially paired, or in radial multiples, or clustered, or in tangential arcs. The vessel end-walls simple, or scalariform and simple. The vessels without vestured pits; without spiral thickening. The axial xylem with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres; at least sometimes including septate fibres, or without septate fibres. The fibres without spiral thickening. The parenchyma typically apotracheal; wood not storied. Tyloses present (occasionally), or absent.
Reproductive type, pollination. Plants hermaphrodite (usually), or dioecious (e.g. in Adenia), or polygamomonoecious (?). Pollination entomophilous.
Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in inflorescences; when aggregated, in cymes. The ultimate inflorescence units cymose. Inflorescences axillary. Flowers usually three bracteate; large; regular; (3–)5(–8) merous; cyclic. Floral receptacle developing an androphore (often), or with neither androphore nor gynophore; markedly hollowed (often), or not markedly hollowed (the receptacle variously shaped). Free hypanthium present (usually), or absent. Hypogynous disk often present (staminodial), or absent.
Perianth with distinct calyx and corolla, or sepaline (the corolla rarely lacking); 5, or 6–16; usually 2 whorled; isomerous. Calyx (3–)5(–8); 1 whorled; polysepalous, or gamosepalous (basally); regular; persistent; imbricate. Corolla when present, (3–)5(–8); 1 whorled; appendiculate (with a conspicuous staminodal corona, this consisting of threadlike filaments or scales, or annular); polypetalous, or gamopetalous (the petals sometimes shortly united basally). Corolla lobes markedly longer than the tube. Corolla imbricate; regular.
Androecium 5, or 20–60. Androecial members free of the perianth; united with the gynoecium (at least, often inserted on the gynophore), or free of the gynoecium; free of one another, or coherent; sometimes 1 adelphous (the stamens of Androsiphonia connate around the gynophore); 1 whorled (? if staminodes absent), or 2 whorled, or 3 whorled. Androecium including staminodes (always?). Staminodes 15–50 (usually many atop the hypanthium within the corolla, constituting the conspicuous petaloid corona, or of filaments, or sometimes represented by a disk around the gynoecium); external to the fertile stamens, or in the same series as the fertile stamens, or internal to the fertile stamens; petaloid, or non-petaloid, or petaloid and non-petaloid. Stamens (4–)5(–10); isomerous with the perianth, or diplostemonous. Anthers dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral. Anther wall initially with more than one middle layer. Tapetum glandular. Pollen grains aperturate; 3–12 aperturate; colporate (to colpoidorate); 2-celled.
Gynoecium (2–)3(–5) carpelled. Carpels reduced in number relative to the perianth to isomerous with the perianth. The pistil 1 celled. Gynoecium syncarpous; synovarious to eu-syncarpous; superior. Ovary 1 locular; stipitate. Styles 1, or (2–)3(–5); free to partially joined; apical. Stigmas 1, or (2–)3(–5); dry type; papillate, or non-papillate; Group II type. Placentation parietal. Ovules in the single cavity 7–100 (several to many); arillate; orthotropous to anatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked (sometimes with filiform apparatus). Endosperm formation nuclear. Embryogeny onagrad, or piperad (occasionally).
Fruit dehiscent, or indehiscent; a capsule, or a berry. Seeds endospermic. Endosperm ruminate (P. foetida), or not ruminate; oily. Embryo well differentiated. Cotyledons 2; flat. Embryo achlorophyllous (1/1); straight.
Seedling. Germination phanerocotylar, or cryptocotylar.
Physiology, phytochemistry. C3 and CAM. C3 physiology recorded directly in Passiflora. CAM recorded directly in Adenia. Often cyanogenic, or not cyanogenic. Cynogenic constituents of the gynocardin group. Alkaloids present (commonly), or absent. Iridoids not detected. Saponins/sapogenins present, or absent. Proanthocyanidins absent. Flavonols absent. Ellagic acid absent (3 species of Passiflora). Aluminium accumulation not found. Sieve-tube plastids S-type.
Geography, cytology. Sub-tropical to tropical. Pantropical and subtropical. X = 6, 9–11.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgrens Superorder Violiflorae; Violales. Cronquists Subclass Dilleniidae; Violales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Malpighiales.
Species 530. Genera about 18; Adenia, Ancistrothyrsus, Androsiphonia, Barteria, Basananthe, Crossostemma, Deidamia, Dilkea, Efulensia, Hollrungia, Mitrostemma, Paropsia, Paropsiopsis, Passiflora, Schlechterina, Smeathmannia, Tetrapathaea, Tryphostemma, Viridivia.
Economic uses, etc. Edible berries (passion fruit) from Passiflora spp., and some cultivated ornamental climbers.
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From the passion-flower at the gate
Illustrations. • Technical details: Passiflora. • Technical details: Adenia (Thonner). • Passiflora alata: Bot. Mag. 66, 1788. • Passiflora amethystina: as P. onychina, Bot. Reg. XXIV, 21 (1838). • Passiflora caerulea: Bot. Mag. 28, 1786.
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: 13th March 2017. delta-intkey.com/angio’.