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Habit and leaf form. Densely pubescent prostrate herbs (with sympodial stems). Plants non-succulent. Annual. Leaves alternate; petiolate; non-sheathing; simple. Lamina dissected, or entire; when deeply dissected, pinnatifid (or pinnately lobed); pinnately veined, or palmately veined; attenuate to the base. Leaves stipulate (with minute stipules), or exstipulate. Lamina margins serrate, or dentate.
Leaf anatomy. Stomata present; anomocytic.
Axial (stem, wood) anatomy. Secretory cavities present; with mucilage. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring, or absent (?).
The vessel end-walls simple. The vessels without vestured pits.
Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers solitary (upturned, on horizontally spreading, seemingly axillary peduncles); regular; 5 merous; cyclic; pentacyclic. Free hypanthium present.
Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; gamosepalous; toothed. Calyx lobes markedly shorter than the tube to markedly longer than the tube. Calyx with the tube broad and flattened; regular; persistent (the sepals sometimes spine-tipped); more or less valvate. Epicalyx present (sometimes, of five bracteoles), or absent. Corolla 5; 1 whorled; polypetalous (inserted in the throat of the calyx); imbricate, or contorted.
Androecium 10. Androecial members free of the perianth (borne on the slightly prolonged hypanthium); free of one another; 2 whorled (5+5). Androecium exclusively of fertile stamens. Stamens 10; diplostemonous; both alternating with and opposite the corolla members; filantherous (the filaments subulate, persistent). Anthers dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate. Pollen shed as single grains. Pollen grains aperturate; (6–)8 aperturate; uniquely aperturate, being bipolar with (3–4 pores at each end; 2-celled.
Gynoecium 10 carpelled (by dedoublement from five?). Carpels increased in number relative to the perianth. The pistil if other than apocarpous, (6–)10 celled. Gynoecium monomerous to syncarpous; semicarpous, or synovarious (the carpels dorsally adnate to the hypanthium, but ventrally free); partly inferior to inferior. Ovary if regarded as syncarpous, (6–)10 locular (with 2–4 of the locules on the side towards the peduncle more or less reduced, or their ovules abortive). Gynoecium stylate. Styles (3–)6–10; free (becoming indurated). Stigmas (3–)6–10; capitate. Placentation axile to apical. Ovules 1 per locule; pendulous; apotropous; non-arillate; anatropous; bitegmic; crassinucellate.
Fruit non-fleshy. The fruiting carpel (if the individual carpels are viewed as separate units) dehiscent; a follicle (one-seeded). Fruit (viewing it as a syncarp) dehiscent; a capsule (with ventrally dehiscent carpels — i.e., representing one-seeded follicles sunk in the hardened receptacle and associated structures). Seeds non-endospermic. Perisperm absent. Embryo well differentiated. Cotyledons 2.
Seedling. Germination phanerocotylar.
Geography, cytology. Holarctic and Paleotropical. Temperate to sub-tropical. Mediterranean to India. N = 6.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rosiflorae; Rosales. Cronquist’s Subclass Rosidae; Rosales. APG III core angiosperms; core eudicot; Superorder Rosanae; malvid. APG IV Order Malvales.
Species 10. Genera 3; Grielum, Neurada, Neuradopsis.
Illustrations. • Grielum tenuifolium: Sweet, Geraniaceae 2 (1824). • Neurada procumbens: Nat. Pflanzenfam. 3 (1894). • Neurada procumbens: Hook. Ic. Pl. 9 (1852).
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: 4th May 2024. delta-intkey.com’.
