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Including Illigeraceae Bl.; excluding Gyrocarpaceae.
Habit and leaf form. Trees, or shrubs, or lianas (i.e., a few scandent); bearing essential oils. Self supporting (mostly), or climbing. Leaves alternate; aromatic; simple, or compound; peltate (often, in Hernandia), or not peltate; if compound, palmate. Lamina dissected, or entire; when dissected, palmatifid; palmately veined; cross-venulate. Leaves exstipulate.
Leaf anatomy. The leaf lamina mostly dorsiventral. Stomata present; mainly confined to one surface (abaxial); mostly paracytic. Hairs present; eglandular (usually exclusively, then nearly always unicellular and lignified, occasionally bracket-shaped), or eglandular and glandular (at least in Illigera, the glands having inicellular stalks and bicellular heads). Complex hairs absent. Adaxial hypodermis present, or absent. Lamina with secretory cavities, or without secretory cavities. Secretory cavities containing oil, or containing mucilage. Cystoliths seemingly absent (?). The mesophyll always with spherical etherial oil cells; containing mucilage cells (in Hernandia), or not containing mucilage cells.
Axial (stem, wood) anatomy. Cork cambium present; at least in Hernandia, initially deep-seated (towards the outside of the primary cortex). Nodes unilacunar (with three traces). 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.
The wood diffuse porous. The vessels small to medium; solitary, radially paired, in radial multiples, and clustered (but mostly solitary). The vessel end-walls simple (typically), or scalariform and simple (occasional bars noted in Hernandia). The vessels without vestured pits. The axial xylem without fibre tracheids; with libriform fibres; including septate fibres (rarely), or without septate fibres. The parenchyma paratracheal. ‘Included’ phloem absent (usually aliform to confluent).
Reproductive type, pollination. Unisexual flowers present, or absent. Plants hermaphrodite, or monoecious.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes; regular; cyclic; tetracyclic.
Perianth with distinct calyx and corolla, or sepaline (?—‘of tepals’); 6–10 (3–5 in each whorl); free; more or less 2 whorled; isomerous; similar in the two whorls. Corolla not fleshy.
Androecium 3–5. Androecial members free of the perianth; free of one another; 1 whorled. Androecium exclusively of fertile stamens, or including staminodes (these in the form of 1–2 nectariferous glands outside the stamens, cf. Lauraceae). Staminodes external to the fertile stamens. Stamens 3–5; oppositisepalous (alternating with the inner perianth whorl). Anthers dehiscing by longitudinal valves. Anther wall of the ‘dicot’ type. Pollen grains nonaperturate; 2-celled.
Gynoecium 1 carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled. Gynoecium monomerous; of one carpel; inferior. Carpel stylate; apically stigmatic; 1 ovuled. Placentation apical. Ovules pendulous; anatropous; bitegmic; crassinucellate. Endosperm formation cellular.
Fruit non-fleshy. The fruiting carpel indehiscent; winged or enclosed in an inflated envelope derived from connate bracteoles. Fruit 1 seeded. Seeds non-endospermic. Cotyledons 2 (fleshy, oily, smooth or ruminate). Embryo straight.
Seedling. Germination phanerocotylar, or cryptocotylar.
Physiology, phytochemistry. Sugars transported as sucrose (Hernandia). Not cyanogenic. Alkaloids present. Anthraquinones detected (Illigera); polyacetate derived. Iridoids not detected. Saponins/sapogenins absent. Proanthocyanidins absent. Flavonols present; kaempferol and quercetin. Ellagic acid absent (Hernandia). Aluminium accumulation not found. Sieve-tube plastids P-type; type I (b).
Geography, cytology. Sub-tropical to tropical. Pantropical.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Magnoliiflorae; Laurales. Cronquist’s Subclass Magnoliidae; Laurales. APG III core angiosperms; Superorder Magnolianae. APG IV Order Laurales.
Species 54. Genera 3; Hazomalania, Hernandia, Illigera.
Illustrations. • Hernandia moerenhoutiana: Bot. Mag. 96 (1870). • Hernandia peltata (Hutchinson). • Illigera celebica and I. megaptera: Duyfjes, Fl. Malesiana 12 (1996).
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: 4th May 2024. delta-intkey.com’.
