Passifloraceae Roussel

Scientific Description

Common name. Passion-flower Family.

Habit and leaf form. Trees and shrubs, or lianas, or 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. Deidamia, Passiflora spp.); when compound, palmate. Leaf blades when simple dissected, or entire; when dissected, palmately lobed; pinnately veined, or palmately veined; cross-venulate. Leaves with stipules, or without stipules. Stipules when present, free of one another; usually small, caducous. Leaves without a persistent basal meristem. Leaf anatomy. Extra-floral nectaries present (on the petioles). Stem anatomy. Nodes tri-lacunar. Secondary thickening developing from a conventional cambial ring, or anomalous; in Adesmia, via concentric cambia.

Reproductive type, pollination. Fertile flowers hermaphrodite (usually), or functionally male, or functionally female, or hermaphrodite, functionally male, and functionally female. Unisexual flowers present, or absent. Plants hermaphrodite (usually), or dioecious (e.g. in Adenia), or polygamomonoecious. Entomophilous.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; in cymes. The terminal inflorescence unit 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 (C rarely lacking); 5, or 6–16; usually 2 -whorled; isomerous. Calyx (3–)5(–8); 1 -whorled; polysepalous, or gamosepalous (basally); imbricate; regular; persistent. Corolla (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); imbricate; regular. Fertile stamens present, or absent (female flowers). 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 (?—when 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); 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. Fertile gynoecium present, or absent (male flowers). Gynoecium (2–)3(–5) carpelled. The pistil 1 celled. Carpels reduced in number relative to the perianth to isomerous with the perianth. Gynoecium syncarpous; synovarious to eu-syncarpous; superior. Ovary unilocular; 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.

Fruit and seed features. Fruit dehiscent, or indehiscent; a capsule, or a berry. Seeds endospermic. Endosperm ruminate (P. foetida), or not ruminate; oily. Embryo well differentiated. Cotyledons 2. Embryo achlorophyllous (1/1); straight. Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C₃ and CAM.

Geography, cytology, number of species. World distribution: pantropical and subtropical. X = 6, 9–11. 530 species.

Economic uses, etc. Edible berries (‘passion fruit’) from Passiflora spp., cultivated ornamental climbers.