| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Petenaeaceae Christenh, M.F.Fay & M.W.Chase

~ Elaeocarpaceae, Malvaceae, Tiliaceae

Habit and leaf form. Hairy trees (to 10 m.), or shrubs. Plants green and photosynthesizing. Leptocaul. In wet tropical forests. Leaves medium-sized; alternate; spiral; flat; ‘herbaceous’ (papery); not imbricate; long, red petiolate; non-sheathing; simple. Lamina entire; ovate; palmately veined; cordate (Tilia-like). Leaves stipulate. Stipules free of one another; minute. Lamina margins minutely denticulate; flat. Leaf development not ‘graminaceous’.

General anatomy. Plants without laticifers.

Leaf anatomy. The leaf lamina dorsiventral.

Axial (stem, wood) anatomy. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow. The axial xylem with vessels.

The wood diffuse porous. The vessels narrow and angular; solitary (mainly). The vessel end-walls scalariform. The vessels with vestured pits. The axial xylem with fibre tracheids; including septate fibres (all septate).

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

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in panicles. The ultimate inflorescence units cymose. Inflorescences many flowered, long pedunculate, pink, tomentose, axillary. Flowers ebracteate (?); ebracteolate; regular, or somewhat irregular (?). Free hypanthium absent.

Perianth sepaline; 4, or 5; 1 whorled. Calyx 4, or 5; 1 whorled; polysepalous, or partially gamosepalous; valvate.

Androecium 8–12. Androecial members free of the perianth; free of one another. Stamens borne on the inner edge of the fleshy, annular disk, 8–12 (each with 2–3 subsessile receptacular glands at the base, which are obscured by a conspicous band of long, villous rose-pink hairs, which give the young flowers a velvety appearance, and through which the anthers protrude in a close circle around the slender style); filantherous (the filaments glabrous). Anthers dorsifixed; versatile; dehiscing via short slits to dehiscing via longitudinal slits (eventually via longitudinal extension of the initial short terminal slits).

Gynoecium 4 carpelled, or 5 carpelled. The pistil 3 celled, or 5 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 4 locular, or 5 locular; sessile (hairy). Gynoecium stylate. Styles 1; apical (hairy below). Stigmas 1; 1 lobed; small, entire, subdiscoid. Placentation axile. Ovules to 50 per locule (or more - "many"); pendulous.

Fruit fleshy; indehiscent; a berry (maroon to black, sweet); to 50 seeded (or more - "many"). Seeds copiously endospermic; very minute to small (1–1.2 mm). Embryo small, straight.

Geography, cytology. Neotropical. Tropical. Northern Central America, Guatemala, Mexico.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Malvales. Cronquist’s Subclass Dilleniidae; Malvales. APG III core angiosperms; core eudicot; Superorder Rosanae; malvid. APG IV Order unassigned.

Species 1 (Petenaea cordata). Genera 1; Petenaea.

General remarks. First described under Elaeocarpaceae by C.L. Lundell in Wrightia 3 (1962), and promoted to family level and referred to Huertiales by Christenhusz et al. in Bot. J. Linn. Soc. 164 (2010).

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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