| | The Families of Angiosperms |
~ Lythraceae.
Including Granateae (Granataceae) D. Don
Habit and leaf form. Small trees, or shrubs (with scattered secretory cells in the cortex and pith, sometimes spiny); leptocaul. Leaves alternate to opposite (sometimes crowded at the tips of the twigs); petiolate; non-sheathing; not gland-dotted; simple. Lamina entire; pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire.
Leaf anatomy. The leaf lamina dorsiventral. Epidermis with crystal idioblasts (these containing large, solitary crystals, on the boundary between palisade and spongy mesophyll). Stomata present; mainly confined to one surface (abaxial); anomocytic. Lamina without secretory cavities. The mesophyll without sclerenchymatous idioblasts; containing crystals. The crystals druses and solitary-prismatic. Minor leaf veins without phloem transfer cells.
Axial (stem, wood) anatomy. Young stems tetragonal in section (with four wings, which are soon lost). Cork cambium present; initially deep-seated. Nodes unilacunar. Primary vascular tissues in a cylinder, without separate bundles; bicollateral. Internal phloem present. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow.
The wood diffuse porous. The vessels very to mderately small; solitary, radially paired, and in radial multiples. The vessel end-walls simple. The vessels with vestured pits; without spiral thickening. The axial xylem without fibre tracheids; with libriform fibres; including septate fibres. The fibres without spiral thickening. The parenchyma scantily paratracheal (or absent). The secondary phloem not stratified. ‘Included’ phloem absent. The wood not storied.
Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite; homostylous.
Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’. Inflorescences when flowers aggregated, terminal, or axillary; comprising axillary fascicles, or the flowers solitary and axillary. Flowers regular; cyclic; polycyclic (by virtue of the androecium). Free hypanthium present (this brightly coloured, far exceeding the inferior ovary).
Perianth with distinct calyx and corolla; 10–16; 2 whorled; isomerous. Calyx 5–8; 1 whorled; polysepalous (in the form of lobes on the hypanthium); regular; becoming leathery; persistent (on the persistent, leathery hypanthium); valvate. Corolla 5–8; 1 whorled; polypetalous; imbricate and crumpled in bud; regular. Petals clawed to sessile.
Androecium 30–100 (‘many’). Androecial members maturing centrifugally; free of the perianth (but inserted inside the hypanthium); free of one another; about 5–7 whorled (?), or 2 whorled (according to Graham et al. 1993). Androecium exclusively of fertile stamens. Stamens 30–100 (‘many’); polystemonous; filantherous (the filaments slender). Anthers dorsifixed; versatile; dehiscing via longitudinal slits; tetrasporangiate. Endothecium developing fibrous thickenings. Pollen shed as single grains. Pollen grains aperturate; 3 aperturate; colporate; 2-celled.
Gynoecium 7–9(–15) carpelled. Carpels isomerous with the perianth to increased in number relative to the perianth. The pistil 7–9(–15) celled. Gynoecium syncarpous; eu-syncarpous; inferior. Ovary 7–9(–15) locular. Epigynous disk present. Gynoecium stylate. Styles 1; apical (slender,simple). Stigmas 1; capitate; wet type; papillate; Group III type. Placentation axile (only, in P. protopunica), or axile and parietal (in P. granatum, where the carpels become superposed in two or three layers by differential growth, the lower with axile placentation, the upper ostensibly parietal). Ovules 20–50 per locule (‘more or less numerous’); anatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3 (uninucleate); not proliferating. Synergids elongated. Endosperm formation nuclear.
Fruit fleshy; indehiscent; a berry (with 2–3 layers of locules, and a leathery rind representing the hypanthium, crowned by the persistent calyx, the seeds embedded in pulp derived from the outer layers of the testas). Seeds non-endospermic. Embryo well differentiated (oily). Cotyledons 2; large, spirally rolled. Embryo achlorophyllous (1/1); straight.
Seedling. Germination phanerocotylar.
Physiology, phytochemistry. C3. C3 physiology recorded directly in Punica. Sugars transported as oligosaccharides + sucrose, or as sugar alcohols + oligosaccharides + sucrose. Inulin recorded (Gibbs 1974). Not cyanogenic. Alkaloids present (one species). Iridoids not detected. Saponins/sapogenins absent. Proanthocyanidins absent. Flavonols absent. Ellagic acid present.
Geography, cytology. Holarctic and Paleotropical. Temperate to tropical. Southeast Europe to the Himalayas, Socotra. X = 8, 9.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Myrtiflorae; Myrtales. Cronquist’s Subclass Rosidae; Myrtales. APG III core angiosperms; core eudicot; Superorder Rosanae; malvid. APG IV Order Myrtales (as a synonym of Lythraceae).
Species 2. Genera 1; only genus, Punica.
General remarks. Differing from Lythraceae in some corolla, androecium, gynoecium and fruit characters, also in the record of rolled seed cotyledons.
Economic uses, etc. ‘Pomegranate’ is the berry of Punica granatum.
Quotations.
Go to, sir; you
were beaten in Italy for picking a kernel out of a pomegranate
(‘All’s Well’, ii., 3)
Nightly she sings on yon
pomegranate tree:
Believe me, love, it was the nightingale
(‘Romeo
and Juliet’, iii., 5)
And does in the pomegranates close
Jewels more
rich than Ormus shows
(Andrew Marvell, ‘Bermudas’)
Illustrations. • Le Maout and Decaisne: Punica granatum. • Punica granatum: Köhler’s Medizinal-Pflanzen 2 (1890). • Punica granatum: flowering, Bot. Mag. 17 (1803). • Punica granatum: fruit, Bot. Mag. 17 (1803). • Punica nana: flowering, Bot. Mag. 17 (1803).
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: 25th April 2024. delta-intkey.com’.
