Family Tetrameristaceae

Tetrameristaceae (H. Hallier) Hutch.

Excluding Pellicieraceae

Habit and leaf form. Trees, or shrubs. Leaves alternate; leathery; subsessile, or sessile; non-sheathing; simple. Lamina entire; conspicuously asymmetric to not conspicuously asymmetric; pinnately veined; cross-venulate; slightly decurrent. Leaves exstipulate. Lamina margins entire.

General anatomy. Plants with ‘crystal sand’, or without ‘crystal sand’.

Leaf anatomy. Extra-floral nectaries present. Stomata present; anomocytic and paracytic.

Adaxial hypodermis present. Lamina dorsiventral. The mesophyll with sclerencymatous idioblasts; containing calcium oxalate crystals. The mesophyll crystals raphides (and commonly crystal sand).

Stem anatomy. Cork cambium present; initially deep-seated. Nodes tri-lacunar. Secondary thickening developing from a conventional cambial ring. Vessel end-walls oblique; scalariform, or scalariform and simple. Vessels without vestured pits. Wood parenchyma apotracheal.

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

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in umbels, or in corymbs. The ultimate inflorescence unit racemose. Inflorescences axillary; umbelliform or compactly corymbiform racemes. Flowers bracteate; bi- bracteolate (the bracteoles persistent or deciduous); small; regular; 4 merous, or 5 merous; cyclic; tetracyclic, or pentacyclic. Free hypanthium absent.

Perianth with distinct calyx and corolla; 8, or 10; 3 whorled (Tetramerista), or 2 whorled; isomerous. Calyx 4 (in two series, in Tetramerista), or 5; 2 whorled (Tetramerista), or 1 whorled; polysepalous (the members with numerous glandular pits adaxially); regular; persistent, or not persistent; imbricate. Corolla 4, or 5; 1 whorled; polypetalous; imbricate (scarcely longer than the sepals); regular; persistent, or deciduous (?).

Androecium 4, or 5. Androecial members free of the perianth; free of one another to coherent (the subulate filaments flattened, perhaps shortly coherent at the base); if coherent, 1 adelphous; 1 whorled. Androecium exclusively of fertile stamens. Stamens 4, or 5; isomerous with the perianth; oppositisepalous; alternating with the corolla members; inflexed in bud (the anthers ultimately inverting to become extrorse). Anthers dorsifixed; dehiscing via longitudinal slits; extrorse. Pollen grains aperturate; 3 aperturate; (constricti-) colporate.

Gynoecium 4 carpelled, or 5 carpelled. Carpels isomerous with the perianth. The pistil 4 celled, or 5 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 4 locular, or 5 locular. Gynoecium stylate. Styles 1; apical. Stigmas 1 (punctate or minutely lobed). Placentation basal to axile. Ovules 1 per locule; ascending; epitropous; anatropous; bitegmic.

Fruit fleshy; indehiscent; a berry; 4 seeded, or 5 seeded. Seeds copiously endospermic. Embryo well differentiated. Cotyledons 2. Embryo straight (basal).

Geography, cytology. Paleotropical and Neotropical. Tropical. Western Malaysia (Tetramerista and southern Venezuela (Pentamerista).

Taxonomy. Subclass Dicotyledonae; Crassinucelli, or Tenuinucelli (?). Dahlgren’s Superorder Theiflorae (?); Theales (?). Cronquist’s Subclass Dilleniidae; Theales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; Order Ericales.

Species 4. Genera 2; Pentamerista, Tetramerista.

Hutchinson 1959, Maguire 1972.