Family Frankeniaceae
Frankeniaceae S.F. GrayHabit and leaf form. Sub shrubs, or herbs; non-laticiferous and without coloured juice. Perennial. Xerophytic (and halophytic). Leaves small; opposite (decussate, often ericoid); rolled; petiolate; simple; epulvinate. Lamina entire; linear. Leaves dubiously stipulate (some Frankenia species), or exstipulate (mostly). Lamina margins revolute. Leaves without a persistent basal meristem. Leaf anatomy. The mesophyll with sclerencymatous idioblasts (around the veins), or without sclerenchymatous idioblasts. Minor leaf veins with phloem transfer cells (Frankenia). Stem anatomy. Internal phloem absent. Secondary thickening developing from a conventional cambial ring, or anomalous; when anomalous, via concentric cambia (Frankenia). ‘Included’ phloem present, or absent. Xylem with libriform fibres. Vessel end-walls simple. Wood partially storied (VPI). Sieve-tube plastids S-type. Reproductive type, pollination. Plants hermaphrodite (usually), or polygamomonoecious (occasionally unisexual — Niederlinia). Pollination entomophilous. Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; in cymes. The ultimate inflorescence unit cymose. Inflorescences axillary; dichasial. Flowers bracteate; (bi-) bracteolate; regular; cyclic; tetracyclic, or pentacyclic. Perianth with distinct calyx and corolla; 8–14; 2 whorled; isomerous. Calyx 4–7; 1 whorled; gamosepalous; shortly blunt-lobed. Calyx lobes markedly shorter than the tube. Calyx regular; persistent; induplicate valvate. Corolla 4–7; 1 whorled; appendiculate (each petal with a scale at the base of the limb, continued down the sides of the claw); polypetalous; imbricate; regular; persistent. Petals clawed; bilobed, or fringed. Androecium (4–)6(–24). Androecial members free of the perianth; all equal, or markedly unequal; more or less coherent; 1 adelphous (basally connate); 2 whorled (usually 3+3). Androecium exclusively of fertile stamens. Stamens (4–)6(–24); isomerous with the perianth, or diplostemonous to polystemonous. Anthers versatile; dehiscing via longitudinal slits; extrorse. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral. Tapetum glandular. Pollen grains aperturate; (2–)3(–4) aperturate, or 6 aperturate; colpate, or rugate; 3-celled. Gynoecium (2–)3(–4) carpelled. The pistil 1 celled. Gynoecium syncarpous; synstylovarious; superior. Ovary 1 locular. The ‘odd’ carpel posterior. Styles 1; apical. Stigmas (2–)3(–4); dry type; papillate; Group II type. Placentation parietal (with (2-)3(-4) placentae). Ovules in the single cavity 12–100 (i.e. ‘many’); ascending; non-arillate; anatropous; bitegmic; pseudocrassinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; large. Synergids hooked. Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal and valvular (enclosed by the calyx). Seeds copiously endospermic. Endosperm not oily (starchy). Seeds with starch. Cotyledons 2. Embryo straight. Seedling. Germination phanerocotylar. Physiology, biochemistry. Not cyanogenic. Alkaloids absent (2 species). Proanthocyanidins present, or absent; when present, cyanidin. Flavonols present; quercetin, or kaempferol and quercetin. Ellagic acid present, or absent (variable in Frankenia). Saponins/sapogenins absent. Aluminium accumulation not found. C3. C3 physiology recorded directly in Frankenia, Hypericopsis. Anatomy non-C4 type (Frankenia, Hypericopsis). Geography, cytology. Mostly temperate and sub-tropical (halophytes). Widespread arid and maritime. X = 10, 15. Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Violiflorae; Tamaricales. Cronquist’s Subclass Dilleniidae; Violales. APG 3 core angiosperms; core eudicot; Superorder Caryophyllanae; Order Caryophyllales. Species 90. Genera 4; Frankenia, Hypericopsis, Anthobryum, Niederleinia. Illustrations. |
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