The families of flowering plants
~ Hugoniaceae, Linaceae.
Habit and leaf form. Trees (with stellate indumentum). Leaves opposite; leathery; petiolate; simple. Lamina entire; pinnately veined (arcuate-anastomosing); cross-venulate. Leaves stipulate. Stipules interpetiolar (large); concrescent; very caducous. Lamina margins entire.
Leaf anatomy. The leaf lamina dorsiventral. Hairs present. Complex hairs present; tufted or stellate (present also on the stipules, sepals and petals).
Axial (stem, wood) anatomy. Primary vascular tissues in a cylinder, without separate bundles; collateral. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow.
The wood diffuse porous. The vessels numerous medium; solitary. The vessel end-walls scalariform. The vessels without vestured pits. The axial xylem with tracheids; probably with vasicentric tracheids (?); with fibre tracheids; without libriform fibres; without septate fibres. Tyloses absent.
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in cymes. Inflorescences terminal and axillary; cymes or cymelike racemes. Flowers pentacyclic. Free hypanthium absent. Hypogynous disk present; extrastaminal; annular (the stamens adnate to its inner side).
Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; gamosepalous (very shortly connate). Calyx lobes markedly longer than the tube. Calyx persistent. Corolla 5; 1 whorled; polypetalous (the petals linear-oblong); imbricate; fleshy; deciduous. Petals spoon-shaped at the base.
Androecium 10. Androecial members free of the perianth; markedly unequal; free of one another; 2 whorled. Stamens 10; diplostemonous; both alternating with and opposite the corolla members. Anthers introrse (ovoid); apiculate. Pollen grains aperturate; 7–9 aperturate; colpate, or colporate (col(por)oidate).
Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth. The pistil 2 celled. Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary 2 locular. Gynoecium stylate. Styles 2; free, or partially joined; apical. Stigmas 2; capitate. Placentation apical. Ovules 2 per locule; long funicled; pendulous; arillate.
Fruit non-fleshy; indehiscent; a nut; 1 seeded. Seeds with fibrous arils.
Geography, cytology. Paleotropical. Tropical. Tropical Africa, Western Malaysia.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgrens Superorder Rutiflorae; Geraniales. Cronquists Subclass Rosidae; Linales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Malpighiales.
Species 3. Genera 1; only genus, Ctenolophon.
Illustrations. • Ctenolophon parvifolius: Hutchinson. • Ctenolophon parvifolius: Fl. Malesiana (1984).
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: 9th January 2018. delta-intkey.com/angio’.