Common name. Passion Flower. Family Passifloraceae.
Habit and leaf form. Lianas, or herbaceous climbers. Leaves cauline. Stem internodes solid. Climbing; tendril climbers (tendrils axillary). Mesophytic, or xerophytic. Leaves alternate (minute); spiral; petiolate (with or without glands); non-sheathing; foetid (West Australian species); simple (usually), or compound; when compound, palmate. Leaf blades dissected, or entire; when dissected, palmately lobed; pinnately veined, or palmately veined; cross-venulate. Leaves with stipules. Stipules free of one another; caducous. Leaf blade margins entire, or dentate (or lobed or palmately lobed or divided). Leaves without a persistent basal meristem. Leaf anatomy. Hairs present, or absent. Extra-floral nectaries present (petiolar), or absent.
Reproductive type, pollination. Fertile flowers hermaphrodite, or functionally male, or functionally female, or hermaphrodite, functionally male, and functionally female. Unisexual flowers present, or absent. Plants hermaphrodite (usually), or dioecious, or polygamomonoecious. Entomophilous.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’ (but reduced to 1 or sometimes 2 flowers), or solitary; in cymes. The terminal inflorescence unit cymose. Inflorescences axillary; inflorescence usually with a simple tendril. Flowers pedicellate, or sessile; bracteate (large, deeply dissected); ebracteolate; large; regular; 5 merous; cyclic. Floral receptacle developing an androphore, or with neither androphore nor gynophore; markedly hollowed, or not markedly hollowed. Free hypanthium present; short. Hypogynous disk present, or absent; annular. Perianth with distinct calyx and corolla; 5, or 6–16; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; polysepalous (mostly), or gamosepalous; blunt-lobed; imbricate; tubular; regular; persistent. Corolla present, or absent (sometimes); 5; 1 -whorled; alternating with the calyx; appendiculate (with a conspicuous staminodal ‘corona’); polypetalous, or gamopetalous; imbricate; regular. Fertile stamens present, or absent (female flowers). Androecial members definite in number. Androecium 5. Androecial members free of the perianth; united with the gynoecium; all equal; coherent (free in upper half); 1 -whorled, or 2 -whorled, or 3 -whorled. Androecium including staminodes. Staminodes 15–50; petaloid, or non-petaloid, or petaloid and non-petaloid. Stamens 5; all more or less similar in shape; isomerous with the perianth; at base of calyx but appear to be inserted at, or near the summit of the gynophore. 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 (elongated gynophore often extending beyond level of fusion with stamens). Gynoecium stylate. Styles 3; free to partially joined; apical. Stigmas 3; capitate. Placentation parietal. Ovules in the single cavity 20–50 (numerous); arillate; orthotropous to anatropous.
Fruit and seed features. Fruit fleshy (pulpy); indehiscent; a berry; 1 celled; 20–100 seeded (numerous). Seeds endospermic. Endosperm ruminate, or not ruminate; oily. Embryo well differentiated. Cotyledons 2. Embryo straight.
Economic uses, etc. Edible berries (‘passion fruits’), cultivated ornamental climbers.
Etymology. From the Latin for "suffering, the suffering of Christ" and "flower"; refers to a fancied resemblance in the parts of the flower to the instruments of Christ's suffering.