The Families of Flowering Plants
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’, 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. Mucilaginous epidermis present. Stomata present; anomocytic.
Minor leaf veins without phloem transfer cells (Idria).
Stem anatomy. Cork cambium present; initially deep-seated, or superficial. Nodes unilacunar (with one trace). Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Xylem with fibre tracheids; with vessels. Vessel end-walls simple. Wood parenchyma apotracheal. Pith with diaphragms.
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, biochemistry. Not cyanogenic. Alkaloids absent (6 species). Iridoids detected; ‘Route I’ type (normal). Proanthocyanidins present, or absent. Ellagic acid present. Saponins/sapogenins present. C3. C3 physiology recorded directly in Fouquieria.
Geography, cytology. Neotropical. Sub-tropical. Warm Southeast U.S.A. and Central America. X = 12.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Corniflorae; Fouquieriales. Cronquist’s Subclass Dilleniidae; Violales. APG (1998) Eudicot; core Eudicot; Asterid; unassigned to Euasterid I or Euasterid II; Ericales. Species 11. Genera 2; only genera, Fouquieria, Idria.
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: 10th April 2008. http://delta-intkey.com’.