The families of flowering plants

L. Watson and M.J. Dallwitz

Rhodoleiaceae (Harms) Nak.

~ Hamamelidaceae.

Habit and leaf form. Trees, or shrubs (of rhododendroid habit). Leaves evergreen (glaucous beneath); alternate (crowded towards the branch tips); spiral; leathery; long petiolate; non-sheathing; simple. Lamina entire; ovate; pinnately veined; cross-venulate; rarely cordate. Leaves exstipulate (as usually described), or stipulate (with reference to the transitional organs between prophylls and leaves). Lamina margins entire.

Leaf anatomy. The leaf lamina dorsiventral. Stomata present; paracytic. The mesophyll with sclerenchymatous idioblasts (these branched, but short and gnarled).

Axial (stem, wood) anatomy. Cork cambium present. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring.

The vessel end-walls scalariform. ‘Included’ phloem absent.

Reproductive type, pollination. Plants hermaphrodite. Floral nectaries present. Nectar secretion from small nectariferous glands around the filaments. Pollination ornithophilous.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in heads. Inflorescences axillary; 5–10 flowered axillary, pendulous capitula; with involucral bracts (these usually broad, imbricate, tomentose); pseudanthial (simulating Camellia flowers). Flowers cyclic; tetracyclic, or pentacyclic. Free hypanthium absent.

Perianth with distinct calyx and corolla, or sepaline (the inner florets of the capitula being apetalous); 5–9; 1 whorled (when the corolla absent), or 2 whorled; anisomerous. Calyx 5; 1 whorled; minute gamosepalous. Corolla when present, 1–4; polypetalous; imbricate; red. Petals clawed (spathulate, exserted).

Androecium (7–)10(–11). Androecial members free of the perianth; free of one another. Androecium exclusively of fertile stamens. Stamens (7–)10(–11); diplostemonous to polystemonous. Anthers basifixed; oblong, non-versatile; dehiscing by longitudinal valves; latrorse; appendaged. The anther appendages apical (via the apiculate connective). Pollen grains aperturate; 3 aperturate; colpate, or colporate (?).

Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth, or isomerous with the perianth. The pistil 1–2 celled. Gynoecium syncarpous; synovarious; partly inferior (sometimes glaucous). Ovary 1–2 locular. Gynoecium stylate. Styles 2 (these long, slender, erect, caducous); free; apical. Stigmas 2. Placentation axile. Ovules 1–20 per locule; more or less horizontal.

Fruit non-fleshy; dehiscent; a capsule (woody, usually bilocular). Capsules four valvular (connate below). Gynoecia of adjoining flowers combining to form a multiple fruit. Fruit 1 seeded (with an additional 20–40 sterile, angular or flattened seeds). Seeds copiously endospermic.

Geography, cytology. Paleotropical. Tropical. Southeast Asia, Malesia. X = 12.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rosiflorae; Hamamelidales. Cronquist’s Subclass Hamamelidae; Hamamelidales. APG 3 core angiosperms; core eudicot; unplaced at Superordinal level; Order Saxifragales (as a synonym of Hamamelidaceae).

Species 1(–7). Genera 1; only genus, Rhodoleia.

General remarks. This compilation of data shows the supposedly ornithophilous Rhodoleia differing from Hamamelidaceae (q.v.) in the polypetalous, imbricate corolla, latrorse anther dehiscence, horizontal ovules, and the valvular capsules forming multiple fruits.

Illustrations. • Rhodoleia championi: Bot. Mag. 76 (1850). • Rhodoleia: flower.

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: 13th March 2017.’.