The Families of Flowering Plants
The Families of Flowering Plants |
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Habit and leaf form. Small shrubs. Plants non-succulent. Xerophytic. Leaves evergreen; opposite; leathery; subsessile to sessile; simple. Lamina entire; pinnately veined. Leaves stipulate. Stipules intrapetiolar (on the petiole); free of one another; minute, vestigial. Lamina margins entire.
Leaf anatomy. Mucilaginous epidermis present. Stomata present; anomocytic.
Lamina dorsiventral. The mesophyll without sclerenchymatous idioblasts (by contrast with Penaeaceae); containing calcium oxalate crystals. The mesophyll crystals druses.
Stem anatomy. Young stems somewhat tetragonal. Cork cambium present; initially superficial. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Vessel end-walls oblique; scalariform.
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers solitary; terminal (on short, axillary branches), or axillary; six bracteate (the bracts in three pairs, persistent); regular; 4 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk absent.
Perianth sepaline; 4; 1 whorled; petaloid; red to pink (rose). Calyx 4; 1 whorled; shortly gamosepalous; four blunt-lobed (nearly to the base). Calyx lobes markedly longer than the tube. Calyx persistent; imbricate.
Androecium 8. Androecial members free of the perianth to adnate (inserted at the base of the calyx); markedly unequal (the oppositisepalous members longer); free of one another; 2 whorled (4+4). Androecium exclusively of fertile stamens. Stamens 8; diplostemonous; alternisepalous (i.e. the outer cycle alternating with the sepals); filantherous (with slender filaments). Anthers dorsifixed (ellipsoid); versatile; dehiscing via longitudinal slits; tetrasporangiate. Pollen shed as single grains. Pollen grains aperturate; 3 aperturate; colporate.
Gynoecium 4 carpelled. Carpels isomerous with the perianth. The pistil 4 celled. Gynoecium syncarpous; synovarious to synstylovarious (the styles free below, but coherent above); superior. Ovary 4 locular (with four grooves and ridges, four lobed); sessile. Gynoecium stylate. Styles 4; partially joined (being coherent above); apical. Stigmas 4. Placentation axile to apical. Ovules 2 per locule; pendulous; collateral; non-arillate; anatropous; bitegmic. Outer integument contributing to the micropyle. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral.
Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal. Fruit 4 seeded. Seeds endospermic. Embryo well differentiated (elongate). Cotyledons 2; linear, fleshy. Embryo central, straight. Testa shining.
Physiology, biochemistry. Aluminium accumulation demonstrated.
Geography, cytology. Cape. Sub-tropical to tropical. Southern Africa.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rosiflorae; Hamamelidales. Cronquist’s Subclass Rosidae; Celastrales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Crossosomatales.
Species 1. Genera 1; only genus, Geissoloma.
Illustrations. • Technical details: Geissoloma (Lindley).
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. This is much more easily achieved using 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 specified attributes, summaries of attributes within groups of taxa, geographical distribution, genera included in each family, classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG), and notes on the APG classification.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 25th November 2009. http://delta-intkey.com’.
