Tetrameristaceae (H. Hallier) Hutch.
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 terminal 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 (1998) Eudicot; core Eudicot; Asterid; unassigned to Euasterid I or Euasterid II; Ericales. Species 4. Genera 2; Pentamerista, Tetramerista.
Hutchinson 1959, Maguire 1972.
Cite this publication as: ‘L. Watson and M. J. Dallwitz (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 14th December 2000. http://biodiversity.uno.edu/delta/’. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993, 1995, 2000), and Watson and Dallwitz (1991) should also be cited (see References).