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The families of flowering plants

L. Watson and M.J. Dallwitz

Strasburgeriaceae Van Tiegh.

~ Ochnaceae.

Excluding Ixerbaceae.

Habit and leaf form. Trees. Leaves large; alternate; petiolate; non-sheathing; simple. Lamina entire; obovate (-spathulate); pinnately veined; cross-venulate; attenuate to the base. Leaves stipulate. Stipules intrapetiolar; concrescent (the two together forming a short, subentire to bifid scale). Lamina margins remotely dentate.

Leaf anatomy. Stomata present; anomocytic. Adaxial hypodermis present (mucilaginous). The mesophyll containing mucilage cells (in addition to the hypodermis).

Axial (stem, wood) anatomy. Secretory cavities present (in the cortex and pith); with mucilage. Internal phloem absent. Cortical bundles present (? — these implied by Metcalfe and Chalk). Secondary thickening developing from a conventional cambial ring.

The vessel end-walls scalariform, or scalariform and simple (?). The axial xylem with tracheids.

Reproductive type, pollination. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers solitary; axillary (short-pedicellate); regular; partially acyclic. The perianth acyclic (the calyx spirally arranged). Free hypanthium absent. Hypogynous disk present; extrastaminal; annular (thick, sinuous, 10-lobed).

Perianth with distinct calyx and corolla; 13–15; consisting of spiralled calyx and whorled corolla. Calyx 8–10; spiralled; polysepalous (the leathery sepals increasing in size acropetally); persistent (below the fruit); closely imbricate. Corolla 5; 1 whorled; polypetalous; imbricate; rather fleshy. Petals sessile.

Androecium 10. Androecial members free of the perianth; all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 10; diplostemonous; both alternating with and opposite the corolla members; filantherous (the filaments stout, subulate). Anthers dorsifixed (oblong, subsagittate); versatile; dehiscing via longitudinal slits (?); introrse. Pollen grains aperturate; 3(–4) aperturate; colporate.

Gynoecium 5 carpelled. Carpels isomerous with the perianth. The pistil 5 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 5 locular (ten ribbed); sessile. Gynoecium stylate. Styles 1; attenuate from the ovary; apical (subulate); about as long as the ovary to much longer than the ovary. Stigmas 1; small, capitate. Placentation axile. Ovules 2 per locule; pendulous; superposed; embryology not recorded.

Fruit fleshy to non-fleshy; globose, indehiscent; capsular-indehiscent, or a berry (‘baccate’, corky-woody when dry, 5–6 cm across). Seeds endospermic (the endosperm fleshy); trigonous, with a broad, winglike, opaque hilum. Embryo well differentiated. Cotyledons 2 (subelliptic). Embryo axile.

Physiology, phytochemistry. Aluminium accumulation not found.

Geography, cytology. Paleotropical. Tropical. New Caledonia.

Taxonomy. Subclass Dicotyledonae; Crassinucelli (?). Dahlgren’s Superorder Theiflorae (?); Theales (?). Cronquist’s Subclass Dilleniidae; Theales. APG III core angiosperms; core eudicot; Superorder Rosanae; malvid. APG IV Order Crossosomatales.

Species 1. Genera 1; only genus, Strasburgeria (S. robusta).

Illustrations. • Strasburgeria robusta: Hutchinson.

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: 15th April 2018.’.