The families of flowering plants
Including Reaumuriaceae Ehrenberg ex Lindley, Tamariscinae (Tamariscaceae) A. St.-Hil.
Habit and leaf form. Small trees, or shrubs, or herbs (rarely, then suffrutescent). Normal plants, or switch-plants; sometimes with the principal photosynthesizing function transferred to stems. Leaves well developed (but small), or much reduced. Leptocaul. Mostly xerophytic (or halophytic). Leaves mostly evergreen; minute, or small; alternate; spiral; commonly subulate or scalelike; fleshy, or membranous; often imbricate (plants often heathlike); sessile (sometimes amplexicaul); sheathing, or non-sheathing; simple; epulvinate. Lamina entire. Leaves exstipulate.
Leaf anatomy. The leaf lamina when not abortive, commonly centric (in Tamarix species with an abortive lamina, the palisade tissue is confined to the underside of the sheath); exhibiting epidermal salt glands (these multicellular and frequently embedded, recorded in all the genera - cf. Frankeniaceae). Stomata present; anomocytic (mostly), or paracytic. Hairs present (but scanty), or absent; when present, eglandular; unicellular. Unicellular hairs simple (simple, thick walled with narrow lumina). Complex hairs absent. Adaxial hypodermis absent. Lamina without secretory cavities. The mesophyll with sclerenchymatous idioblasts, or without sclerenchymatous idioblasts; exhibiting solitary and cluster crystals which have been identified as gypsum rather than calcium oxalate. Minor leaf veins with phloem transfer cells (Tamarix), or without phloem transfer cells (Myricaria).
Axial (stem, wood) anatomy. Young stems with solid internodes. Pith often comprising thick-waled cells. Secretory cavities absent. Cork cambium present; initially deep-seated (rarely, sometimes with a succession of phellogens), or initially superficial. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays wide in Tamarix.
The wood ring porous (Myricaria), or semi-ring porous (in some Tamarix species), or diffuse porous. The vessels small, or medium; solitary, or radially paired, or in radial multiples, or clustered. The vessel end-walls horizontal; simple. The vessels without vestured pits; without spiral thickening. The axial xylem without fibre tracheids; with libriform fibres; without septate fibres. The fibres without spiral thickening. The parenchyma paratracheal. The secondary phloem not stratified. Included phloem absent. The wood partially storied (VPI). Tyloses absent.
Reproductive type, pollination. Plants hermaphrodite, or dioecious.
Inflorescence, floral, fruit and seed morphology. Flowers solitary (Hololachne, Reaumuria), or aggregated in inflorescences; when aggregated, in racemes, or in spikes, or in panicles. The ultimate inflorescence units racemose. Inflorescences in racemes, spikes or panicles. Flowers ebracteolate; small; regular; mostly, when A definite, 4–5(–6) merous; cyclic. Free hypanthium absent. Hypogynous disk present, or absent; extrastaminal, or intrastaminal, or extrastaminal and intrastaminal; of separate members, or annular.
Perianth with distinct calyx and corolla; 8, or 10, or 12; 2 whorled; isomerous. Calyx 4, or 5(–6); 1 whorled; polysepalous (usually), or gamosepalous (sometimes connate below); when gamosepalous, conspicuously blunt-lobed; regular; persistent; imbricate. Corolla 4, or 5(–6); 1 whorled; appendiculate (each petal of Reaumuria exhibiting a pair of scalelike appendages inside at the base), or not appendiculate; polypetalous; imbricate; regular; white, or pink; persistent, or deciduous.
Androecium 4–6, or 8–12 (often twice as many as the petals), or 15–100 (often more or less numerous). Androecial members branched (when numerous), or unbranched; free of the perianth; free of one another, or coherent (when many, often joined at their bases or in bundles); when joined 1 adelphous, or 5 adelphous. Androecium exclusively of fertile stamens. Stamens 4–6, or 8–12 (often twice as many as the petals), or 15–100 (often more or less numerous); isomerous with the perianth to polystemonous; when definite, oppositisepalous. Anthers dorsifixed; dehiscing via longitudinal slits; extrorse, or latrorse, or introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with more than one middle layer (2). Tapetum glandular. Pollen shed in aggregates, or shed as single grains; when in aggregates, in tetrads. Pollen grains aperturate; (2–)3(–4) aperturate; colpate; 2-celled (in Myricaria).
Gynoecium (2–)3–4(–5) carpelled. Carpels reduced in number relative to the perianth, or isomerous with the perianth. The pistil 1 celled, or (2–)3–4(–5) celled. Gynoecium syncarpous; synovarious, or synstylovarious; superior. Ovary 1 locular (but the placental partitions sometimes sufficiently deeply intruded as to simulate loculi, especially basally and apically); sessile. Gynoecium non-stylate (the stigmas sessile in Myricaria), or stylate. Styles when present, (2–)3–4(–5); free, or partially joined; apical. Stigmas (2–)3–4(–5); wet type; non-papillate; Group IV type. Placentation parietal, or basal to parietal (Tamarix). Ovules in the single cavity 4–100 (2many on each placenta); funicled; ascending; anatropous; bitegmic; weakly crassinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Adoxa-type, or Drusa-type, or Fritillaria-type, or Chrysanthemum-type. Polar nuclei fusing only after one has been fertilized, or fusing simultaneously with the male gamete (?). Antipodal cells formed; 3; not proliferating; ephemeral. Synergids pear-shaped, or hooked (rarely with filiform apparatus). Endosperm formation cellular, or nuclear. Embryogeny solanad.
Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal. Seeds scantily endospermic. Endosperm not oily (starchy). Seeds conspicuously hairy (either covered with long hairs, or these forming a coma at one end). Seeds with starch. Embryo well differentiated. Cotyledons 2. Embryo straight.
Seedling. Germination phanerocotylar.
Physiology, phytochemistry. C3. C3 physiology recorded directly in Myricaria, Reaumuria, Tamarix. Anatomy non-C4 type (Reaumuria, Tamarix). Sugars transported as sucrose (in Tamarix). Not cyanogenic. Alkaloids present, or absent. Arbutin absent. Saponins/sapogenins absent. Proanthocyanidins present, or absent; cyanidin. Flavonols present; kaempferol and quercetin (or tamarixin). Ellagic acid present, or absent (Tamarix being variable). Aluminium accumulation not found.
Geography, cytology. Holarctic and Paleotropical. Temperate and sub-tropical. Desert, steppe and shores, widespread in temperate and subtropical Eurasia and Africa - absent from the Americas, Malaysia and Australasia. X = 12.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgrens Superorder Violiflorae; Tamaricales. Cronquists Subclass Dilleniidae; Violales. APG 3 core angiosperms; core eudicot; Superorder Caryophyllanae; Order Caryophyllales.
Species 120. Genera 4; Hololachna, Myricaria, Reaumuria, Tamarix.
Illustrations. • Le Maout and Decaisne: Tamarix. • Tamarix senegalensis: Thonner. • Reaumuria hypericoides: Lindley. • Tamarix gallica (as T. anglica): Eng. Bot. 261, 1864. • Tamarix gallica (B. Ent.).
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: 24th October 2017. delta-intkey.com/angio’.