| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Gyrocarpaceae Dum.

~ Hernandiaceae.

Habit and leaf form. Small trees, or shrubs, or lianas. Self supporting, or climbing. Mesophytic. Leaves alternate; petiolate; non-sheathing; aromatic (?); simple. Lamina dissected, or entire; when dissected, palmatifid; palmately veined; cross-venulate. Leaves exstipulate; leaf development not ‘graminaceous’.

Leaf anatomy. The leaf lamina dorsiventral. Stomata mainly confined to one surface (abaxial); anomocytic. Hairs present; exclusively eglandular; unicellular. Unicellular hairs simple. Complex hairs absent. Adaxial hypodermis present, or absent. Lamina without secretory cavities. Cystoliths present (spherical in Gyrocarpus, radiately branched in Sparattanthelium). The mesophyll with spherical etherial oil cells; not containing mucilage cells; containing crystals. The crystals small, acicular.

Axial (stem, wood) anatomy. Secretory cavities absent. Cork cambium present; initially superficial. Nodes unilacunar (with two 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 medium; mostly solitary, or radially paired, in radial multiples, and clustered. The vessel end-walls simple. The axial xylem with fibre tracheids, or without fibre tracheids (?); with libriform fibres. The parenchyma paratracheal; wood not storied.

Reproductive type, pollination. Unisexual flowers present. Plants andromonoecious, or polygamomonoecious.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes, in corymbs, and in panicles. The ultimate inflorescence units cymose. Inflorescences dense thyrses. Flowers cyclic. Free hypanthium absent.

Perianth sepaline; (4–)8 (male flowers), or 2 (bisexual flowers); joined; 1 whorled. Calyx if the perianth be so interpreted, (4–)8 (male flowers), or 2 (or at least, 2-lobed, in bisexual flowers); gamosepalous; persistent; in bisexual flowers accrescent (and winged); in male flowers, imbricate.

Androecium 3–5, or 6–9 (when staminodes present). Androecial members free of the perianth; free of one another; 1 whorled, or 2 whorled. Androecium exclusively of fertile stamens, or including staminodes (these sometimes present in male as well as in bisexual flowers). Staminodes when present, 3–7. Stamens 3–5. Anthers basifixed; dehiscing by longitudinal valves; latrorse. Pollen grains nonaperturate; 2-celled (in both genera).

Gynoecium 1 carpelled. The pistil 1 celled. Gynoecium monomerous; of one carpel; inferior. Carpel 1 ovuled. Placentation marginal.

Fruit non-fleshy. The fruiting carpel indehiscent (winged via the persistent, accrescent lobes of the perianth). Seeds non-endospermic. Cotyledons 2 (leafy, convolute).

Physiology, phytochemistry. Alkaloids present. Aluminium accumulation not found. Sieve-tube plastids P-type; type I (b).

Geography, cytology. Sub-tropical to tropical. Pantropical and subtropical.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Magnoliiflorae; Laurales. Cronquist’s Subclass Magnoliidae; Laurales. APG III core angiosperms; Superorder Magnolianae. APG IV Order Laurales (as a synonym of Hernandiaceae).

Species 22. Genera 2; Gyrocarpus, Sparattanthelium.

General remarks. Differing from Hernandiaceae in the 1-whorled, joined perianth members and the marginal placentation of the ovary, also in recorded data on leaf and wood anatomy.

Illustrations. • Le Maout and Decaisne: Gyrocarpus, Sparattanthelium. • Gyrocarpus americanus: from Jacquin, Fragmenta Botanica (1809). • Gyrocarpus americanus: 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: 8th June 2026. delta-intkey.com’.

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