Family Aphanopetalaceae

Aphanopetalaceae Endl.

~ Cunoniaceae in older systems

Habit and leaf form. Straggling lianas. Climbing; scrambling. Mesophytic, or xerophytic (?). Leaves opposite (4–10 cm long); leathery; simple (not articulated on the petiole). Lamina entire; ovate, or lanceolate (or elliptic-lanceolate); obtuse or shortly acuminate, attenuate at the base. Leaves stipulate, or exstipulate (or the small stipules fugaceous?). Stipules small. Lamina margins obtusely serrate, or entire.

Reproductive type, pollination. Fertile flowers hermaphrodite. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in panicles. The ultimate inflorescence unit cymose. Inflorescences axillary; few flowered, short cymes or sometimes loose panicles. Flowers small (about 12 mm long); regular; 4 merous; tricyclic, or tetracyclic. Free hypanthium present (adnate to the lower half of the ovary wall, above which the perianth members and stamens separate).

Perianth with distinct calyx and corolla, or sepaline (the presence of petals can vary among different flowers of the same individual); 4, or 8; 1 whorled, or 2 whorled; when 2-whorled, isomerous. Calyx 4 (white or cream, petaline); 1 whorled; basally gamosepalous; regular; persistent; accrescent; imbricate. Corolla when present 4 (minute); 1 whorled; when present, alternating with the calyx; polypetalous; regular.

Androecium 8. Androecial members free of the perianth, or adnate (each petal segment, when present, basally adnate with the staminal filament in the same radius above the level of separation from the ovary); all equal; free of one another; 2 whorled. Androecium exclusively of fertile stamens. Stamens 8; diplostemonous. Anthers almost basifixed; non-versatile.

Gynoecium 4 carpelled. Carpels isomerous with the perianth. The pistil 4 celled. Gynoecium syncarpous; synovarious to synstylovarious; partly inferior (one-quarter to half inferior). Ovary 4 locular. Gynoecium stylate. Styles 4; partially joined (separating only near their apices); apical. Stigmas 4; dry type (?); papillate (?); Group II type (?). Placentation axile. Ovules 1 per locule; pendulous; non-arillate; anatropous.

Fruit non-fleshy; indehiscent; a nut (surrounded by the persistent calyx). Seeds endospermic (?); minute. Cotyledons 2. Embryo straight.

Geography, cytology. Australian. Temperate. Southern Queensland and New South Wales (A. resinosum) and S.W. Western Australia (A. clematidum).

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rosiflorae; Cunoniales. Cronquist’s Subclass Rosidae; Rosales. APG 3 core angiosperms; core eudicot; unplaced at Superordinal level; Order Saxifragales.

Species 2. Genera 1; Aphanopetalum.

Illustrations.
• Aphanopetalum resinosum: A. Forster, 1938.

Miscellaneous. This description lacks information on “esoteric characters” (anther development, embryology, phytochemistry, etc.); and specimens should be examined with special reference to features diagnostic for Cunoniaceae (e.g., zigzag micropyle?).

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