| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Dulongiaceae J.G. Agardh

Alternatively Phyllonomaceae Rusby, Phyllonomataceae J.K Small; ~ Grossulariaceae.

Habit and leaf form. Trees, or shrubs. Leaves alternate; simple; not peltate. Lamina entire; acuminate. Leaves stipulate. Stipules caducous (small, fringed). Lamina margins entire, or serrate.

Axial (stem, wood) anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in fascicles. The ultimate inflorescence units cymose. Inflorescences epiphyllous; cymose false umbels. Flowers small (green); regular; (4–)5 merous; cyclic.

Perianth with distinct calyx and corolla; 8, or 10; 2 whorled; isomerous. Calyx (4–)5; 1 whorled; polysepalous; regular; open in bud. Corolla (4–)5; 1 whorled; polypetalous; valvate; regular; green.

Androecium (4–)5. Androecial members free of the perianth; all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens (4–)5; isomerous with the perianth; alternating with the corolla members; shortly filantherous. Anthers small, bilobed. Pollen grains aperturate; 2–3 aperturate; colpate, or colporate (colporoidate).

Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled. Gynoecium syncarpous; synovarious; inferior. Ovary 1 locular. Epigynous disk present (intrastaminal, large, pulvinate). Gynoecium stylate. Styles 2; free; apical; shorter than the ovary (very short, divaricate). Stigmas 2. Placentation parietal. Ovules in the single cavity 50–100 (‘many’); biseriate.

Fruit fleshy; indehiscent; a berry (incompletely bilocular); 3–6 seeded. Seeds endospermic. Testa rugose.

Physiology, phytochemistry. Aluminium accumulation demonstrated.

Geography, cytology. Neotropical. Tropical. Mexico to Peru.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Corniflorae; Cornales (?). Cronquist’s Subclass Rosidae; Rosales. APG III core angiosperms; core eudicot; Superorder Asteranae; campanulid. APG IV Order Aquifoliales.

Species 8. Genera 1; only genus, Phyllonoma (Dulongia Kunth).

General remarks. Description very inadequate.

Illustrations. • Phyllonoma laticuspis: Nat. Pflanzenfam. III (1891). • Phyllonoma ruscifolia, as Dulongia acuminata: Humboldt et al., Nova genera et species plantarum 7 (1825).

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: 8th June 2026. delta-intkey.com’.

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