The families of flowering plants
Habit and leaf form. Small trees, or shrubs (with long- and short-shoots, the petioles of the leaves on the long-shoots hardening and persisting as spines when the blades fall, the short-shoots axillary to the spines and producing clustered leaves that do not form spines). Switch-plants; more or less cactoid, with succulent, photosynthetic stems, or with the principal photosynthesizing function transferred to stems. Plants succulent (often with parenchymatized xylem storing water). Xerophytic. Leaves deciduous (often ephemeral, produced after rain); small; alternate; fleshy; petiolate; non-sheathing; simple. Lamina entire; pinnately veined. Leaves exstipulate.
Leaf anatomy. The leaf lamina dorsiventral, or bifacial. Mucilaginous epidermis present. Stomata present; on both surfaces; anomocytic. Minor leaf veins without phloem transfer cells (Idria).
Axial (stem, wood) anatomy. Pith with diaphragms, or without diaphragms. Nodes unilacunar (with one trace). Primary vascular tissues in a cylinder, without separate bundles, or comprising a ring of bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring.
The wood ring porous to semi-ring porous. The vessels very small; in Fouqueria solitary, radially paired, in radial multiples, clustered, and in tangential arcs. The vessel end-walls scalariform, or simple. The vessels without vestured pits; without spiral thickening. The axial xylem with fibre tracheids; without septate fibres. The fibres without spiral thickening. The parenchyma apotracheal. Included phloem absent. The wood not storied.
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences. Inflorescences terminal, or axillary. Flowers showy, medium-sized; regular to somewhat irregular; sometimes slightly zygomorphic (curved); cyclic; tetracyclic, or pentacyclic. Free hypanthium absent. Hypogynous disk present; annular (small).
Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; polysepalous; persistent; much imbricate. Corolla 5; gamopetalous; imbricate; tubular; unequal but not bilabiate, or regular; yellow (Idria), or red (Fouquieria).
Androecium 10–15(–23). Androecial members free of the perianth; all equal, or markedly unequal; free of one another; 1–2 whorled (the antesepalous members sometimes larger and more outwardly directed, simulating two whorls). Androecium exclusively of fertile stamens (?). Stamens 10–15(–23); diplostemonous, or triplostemonous; both alternating with and opposite the corolla members; long filantherous (exserted, the filaments often hairy at the base). Anthers dorsifixed; dehiscing via longitudinal slits; tetrasporangiate. Pollen shed as single grains. Pollen grains aperturate; 3 aperturate; colporate; 2-celled.
Gynoecium 3 carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled. Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary 1 locular. Gynoecium stylate. Styles 3; partially joined (the style branched near or above the middle); apical. Stigmas 3 (terminal). Placentation parietal (above, with deeply intruded placentas, axile at the base). Ovules in the single cavity (6–)14–18(–20); ascending; anatropous; bitegmic; tenuinucellate. Outer integument not contributing to the micropyle. Endothelium differentiated. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids pear-shaped. Endosperm formation cellular. Embryogeny asterad.
Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal. Seeds endospermic, or non-endospermic. Endosperm when present, oily. Seeds winged. Embryo well differentiated. Cotyledons 2. Embryo straight (spathulate).
Seedling. Germination phanerocotylar.
Physiology, phytochemistry. C3. C3 physiology recorded directly in Fouquieria. Not cyanogenic. Alkaloids absent (6 species). Iridoids detected; Route I type (normal). Saponins/sapogenins present. Proanthocyanidins present, or absent. Ellagic acid present.
Geography, cytology. Neotropical. Sub-tropical. Warm Southeast U.S.A. and Central America. X = 12.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgrens Superorder Corniflorae; Fouquieriales. Cronquists Subclass Dilleniidae; Violales. APG III core angiosperms; core eudicot; Superorder Asteranae. APG IV Order Ericales.
Species 11. Genera 2; only genera, Fouquieria, Idria.
Illustrations. • Fouquieria splendens: Bot. Mag. 136 (1910). • Fouquieria formosa (Hutchinson).
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: 5th March 2018. delta-intkey.com/angio’.