Rhabdodendraceae (Engl.) Prance
~ Rutaceae p.p.
Habit and leaf form. Tall, fastigiate or subpyramidal shrubs. Leaves alternate; leathery; gland-dotted; simple. Lamina entire. Leaves stipulate, or exstipulate. Stipules if present, caducous.
Leaf anatomy. Stomata present; anomocytic. Hairs present. Complex hairs present; peltate (short-stalked, with siliceous inclusions).
Lamina with secretory cavities (also with scattered fatty bodies). Secretory cavities containing resin; Secretory cavities lysigenous. The mesophyll with sclerencymatous idioblasts (traversed by fibre-like, simple or branched sclereids representing prolongations from the vein ends, and many of the mesophyll cells with silicified walls).
Stem anatomy. Nodes multilacunar. Internal phloem absent. Secondary thickening developing from a conventional cambial ring, or anomalous; via concentric cambia, or from a single cambial ring. ‘Included’ phloem present. Xylem with vessels. Vessel end-walls simple. Wood parenchyma largely apotracheal, or paratracheal (then very scanty-diffuse). Sieve-tube plastids P-type; type I (b).
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes, or in racemes. The terminal inflorescence unit cymose, or racemose. Inflorescences axillary (or supra-axillary); racemes, or racemelike cymes with terminal flowers. Flowers regular; cyclic; polycyclic (by virtue of the androecium). Free hypanthium present (short, the flowers slightly perigynous). Hypogynous disk absent.
Perianth with distinct calyx and corolla; 10 (or the calyx more or less entire); 2 whorled. Calyx basically 5 (but the lobes short or obscure); 1 whorled; gamosepalous; five lobulate to blunt-lobed, or entire; regular; imbricate (when lobed), or open in bud. Corolla 5 (sepal-like); 1 whorled; polypetalous (the petals glandular-punctate); imbricate and valvate (slightly imbricate below and valvate above, or cochlear); regular; deciduous (caducous).
Androecium 25–50. Androecial members when the stamens not developing more or less simultaneously, weakly maturing centripetally; free of the perianth; free of one another; more or less 3 whorled. Androecium exclusively of fertile stamens. Stamens 25–50; polystemonous; erect in bud; shortly filantherous (the filaments flattened, persistent). Anthers basifixed (elongated, apically emarginate, caducous); non-versatile; dehiscing via longitudinal slits; tetrasporangiate. Pollen shed as single grains. Pollen grains aperturate; 3(–4) aperturate; colporate; 3-celled.
Gynoecium 1 carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled. Gynoecium monomerous; of one carpel; superior. Carpel stylate; with a gynobasic style (the style thick, virtually basal, externally stigmatic for half to all of its length); 1(–2) ovuled (the second, if present, abortive). Placentation basal. Ovules epitropous; orthotropous, or hemianatropous; unitegmic.
Fruit scarcely fleshy, or non-fleshy. The fruiting carpel indehiscent; drupaceous (globular, borne on the woody pedicel and shortly stipitate within the cupular hypanthium, the exocarp thin and eventually crustaceous, the endocarp slightly woody). Fruit 1 seeded. Seeds non-endospermic. Embryo well differentiated. Cotyledons 2 (thick, fleshy). Embryo bent (the radicle bent inwards towards the hilum).
Physiology, biochemistry. Cyanogenic.
Geography, cytology. Neotropical. Tropical. North Brazil, Guianas. X = 10.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Caryophylliflorae (? — reassigned on the basis of rbcL sequencing, Chase et al. 1993); near Caryophyllales (?). Cronquist’s Subclass Rosidae; Rosales. APG (1998) Eudicot; core Eudicot; neither Rosid nor Asterid; Caryophyllales. Species 4. Genera 1; only genus, Rhabdodendron.
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).