Family Magnoliaceae
Magnoliaceae Juss.Habit and leaf form. Trees and shrubs; bearing essential oils, or without essential oils. Mesophytic. Leaves evergreen, or deciduous; medium-sized, or large; alternate; spiral; ‘herbaceous’, or leathery; petiolate; sheathing (via the stipules); gland-dotted, or not gland-dotted; aromatic, or without marked odour; simple. Lamina dissected (Liriodendron), or entire; (of Liriodendron) pinnatifid, or palmatifid (with truncate or emarginate apices); pinnately veined, or palmately veined; cross-venulate. Leaves stipulate (the stipules large, sheathing, enclosing the terminal buds). Stipules ochreate (often), or not ochreate; caducous. Leaves without a persistent basal meristem. Leaf anatomy. Stomata paracytic, or anomocytic and paracytic. Adaxial hypodermis present, or absent. The mesophyll with spherical etherial oil cells, or without etherial oil cells (?); containing mucilage cells, or not containing mucilage cells. Minor leaf veins without phloem transfer cells (Magnolia). Stem anatomy. Cork cambium present; initially superficial. Nodes penta-lacunar, or multilacunar (with five or more traces). Cortical bundles absent. Medullary bundles absent. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones, or not stratified. ‘Included’ phloem absent. Xylem with tracheids, or without tracheids; with fibre tracheids, or without fibre tracheids. Vessel end-walls scalariform, or simple, or scalariform and simple. Vessels without vestured pits. Wood parenchyma apotracheal (terminal). Sieve-tube plastids S-type, or P-type and S-type; when P-type, type I (b). Pith with diaphragms, or without diaphragms. Reproductive type, pollination. Plants hermaphrodite (usually), or monoecious (Kmeria). Pollination entomophilous; via beetles. Inflorescence, floral, fruit and seed morphology. Flowers usually solitary; terminal, or axillary; bracteate (the bracts spathaceous); large; regular; partially acyclic, or acyclic. The perianth acyclic, the androecium acyclic, and the gynoecium acyclic, or the androecium acyclic and the gynoecium acyclic. Floral receptacle not markedly hollowed (usually markedly elongated). Free hypanthium absent. Hypogynous disk absent. Perianth with distinct calyx and corolla (rarely), or sequentially intergrading from sepals to petals, or petaline (usually); 6–18; free; when not spiralled, 3–4 whorled; white, or cream, or pink; deciduous. Androecium 50–200 (‘many’). Androecial members maturing centripetally; free of the perianth; free of one another; spiralled. Androecium exclusively of fertile stamens. Stamens 50–200 (‘many’); more or less filantherous, or laminar (the four paired microsporangia embedded, the stamens often more or less strap-shaped). Anthers adnate; non-versatile; dehiscing via longitudinal slits, or dehiscing by longitudinal valves; extrorse (Liriodendron), or latrorse to introrse (usually, the thecae nearly lateral); bilocular; tetrasporangiate; appendaged (often, by prolongation of the connective), or unappendaged. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads isobilateral, or decussate. Anther wall initially with more than one middle layer (up to four). Tapetum glandular. Pollen shed as single grains. Pollen grains aperturate; 1 aperturate; sulcate; 2-celled. Gynoecium (2–)20–200 carpelled; apocarpous; eu-apocarpous; superior. Carpel fully closed, or incompletely closed; stylate; apically stigmatic; 2(–20) ovuled. Placentation marginal. Ovules funicled; pendulous; biseriate (on the ventral suture); 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 pear-shaped. Endosperm formation cellular. Embryogeny onagrad. Fruit fleshy, or non-fleshy; an aggregate. The fruiting carpels coalescing into a secondary syncarp (woody or fleshy), or not coalescing. The fruiting carpel dehiscent, or indehiscent; a follicle, or samaroid (Liriodendron), or baccate. Seeds endospermic. Endosperm oily. Seeds usually large. Embryo well differentiated (usually very small, larger in Liriodendron). Embryo achlorophyllous (2/2). Seedling. Germination phanerocotylar. Physiology, biochemistry. Cyanogenic. Cynogenic constituents tyrosine-derived. Alkaloids present (often), or absent. Iridoids not detected. Proanthocyanidins present (rarely), or absent; when present, cyanidin. Flavonols present; kaempferol and quercetin. Ellagic acid absent (2 genera, 8 species). Arbutin absent. Aluminium accumulation demonstrated. Sugars transported as sucrose (Liriodendron), or as sugar alcohols + oligosaccharides + sucrose (Magnolia kobus). C3. C3 physiology recorded directly in Magnolia. Geography, cytology. Temperate to tropical. Eastern Asia and America. X = 19. Supposed basic chromosome number of family: 19. Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Magnoliiflorae; Magnoliales. Cronquist’s Subclass Magnoliidae; Magnoliales. APG 3 core angiosperms; Superorder Magnolianae; Order Magnoliales. Species 230. Genera 7; Elmerrillia, Kmeria, Liriodendron, Magnolia, Manglietia, Michelia, Pachylarnax. Illustrations. |
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