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The families of flowering plants

L. Watson and M.J. Dallwitz

Gisekiaceae Nak.

~ Phytolaccaceae, Molluginaceae.

Habit and leaf form. Herbs (often diffuse with prostrate branches). Plants more or less succulent, or non-succulent. Annual to perennial. Mesophytic, or xerophytic. Leaves (pseudo-) whorled, or opposite; ‘herbaceous’, or fleshy; simple. Lamina entire; spathulate or linear. Leaves exstipulate. Lamina margins entire. Leaf development not ‘graminaceous’.

Leaf anatomy. The leaf lamina dorsiventral. Stomata present; anomocytic. Cystoliths present.

Axial (stem, wood) anatomy. Nodes unilacunar. Secondary thickening developing from a conventional cambial ring.

The vessel end-walls simple.

Reproductive type, pollination. Fertile flowers functionally male, or functionally female. Plants dioecious.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes. The ultimate inflorescence units cymose. Inflorescences axillary; loose to dense axillary cymes. Flowers bracteate; bracteolate; pedicellate to sessile, small; regular. Floral receptacle with neither androphore nor gynophore. Free hypanthium absent.

Perianth sepaline (corolla absent); 5; 1 whorled. Calyx 5; 1 whorled; polysepalous; regular (the sepals equal, herbaceous with membranous margins); imbricate.

Androecium in male flowers, 5–15. Androecial members branched, or unbranched (in that the stamens often inserted in pairs or triplets); free of the perianth; basally coherent, or free of one another (?). Androecium exclusively of fertile stamens. Stamens 5–15; isomerous with the perianth to triplostemonous; filantherous (the subulate filaments basally compressed). Anthers dorsifixed; dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Microsporogenesis simultaneous. Anther wall of the ‘monocot’ type. Tapetum glandular. Pollen grains aperturate; 3-celled.

Gynoecium 3–5 carpelled. Carpels reduced in number relative to the perianth to isomerous with the perianth. Gynoecium apocarpous; eu-apocarpous; superior. Carpel stylate; with the short, ventrally decurrent style internally stigmatose; 1 ovuled. Placentation basal. Ovules campylotropous, or amphitropous (?); bitegmic; crassinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Synergids hooked (with filiform apparatus). Endosperm formation nuclear.

Fruit non-fleshy; an aggregate (5-carpelled). The fruiting carpel indehiscent; membranous. Seeds non-endospermic. Perisperm present. Embryo “annular” or curved.

Physiology, phytochemistry. C4. C4 physiology recorded directly in all seven accepted species, including the widespread Gisekia pharnaceoides. Anatomy C4 type. Betalains present. Proanthocyanidins absent.

Geography, cytology. Holarctic, Paleotropical, and Cape. Sub-tropical and tropical. Arabia, tropical and South Africa to India, Sri Lanka and Indo-china.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Caryophylliflorae; Caryophyllales. Cronquist’s Subclass Caryophyllidae; Caryophyllales. APG 3 core angiosperms; core eudicot; Superorder Caryophyllanae; Order Caryophyllales.

Species 5–7. Genera 1; Gisekia.

Illustrations. • Gisekia pharnaceoides (as molluginioides): R. Wight, Ic. Pl. Indiae Orientalis (1850). • Floral diagrams of Gisekia: Bot. Jahrb. 37 (1881).

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.’.