The families of flowering plants
Habit and leaf form. Trees and shrubs; resinous. Leaves alternate; petiolate; compound; ternate, or pinnate (usually), or unifoliolate (rarely simple). Lamina pinnately veined; cross-venulate. Leaves exstipulate.
Leaf anatomy. Lamina with secretory cavities (in the phloem of the petiole). Secretory cavities containing resin. Minor leaf veins without phloem transfer cells.
Axial (stem, wood) anatomy. Secretory cavities present (in the primary phloem); with resin. Cork cambium present; initially superficial. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring.
The vessel end-walls simple. The parenchyma paratracheal. Included phloem absent.
Reproductive type, pollination. Plants dioecious. Female flowers without staminodes. Gynoecium of male flowers vestigial, or absent.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in panicles. The ultimate inflorescence units cymose. Inflorescences many-flowered panicles. Flowers bracteate; (bi-) bracteolate; small; regular; cyclic. Hypogynous disk present (in male flowers), or absent (minute or lacking in female flowers).
Perianth sepaline, or absent (if the calyx is considered to be bracteal); 1–5. Calyx 1–2 (or missing, in male flowers), or 2–5 (in female flowers); polysepalous (small, scarious).
Androecium in male flowers, 3–5. Androecial members adnate; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 2–5; isomerous with the perianth to diplostemonous; filantherous (the filaments very short, adnate to the disk). Anthers basifixed (large, ovoid); dehiscing via longitudinal slits; latrorse; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral. Anther wall initially with more than one middle layer (3); of the basic type. Tapetum glandular. Pollen grains aperturate; about 3–8 aperturate (not sharply delimited); colpate (colpoidate), or foraminate, or rugate; 2-celled.
Gynoecium 3 carpelled. Carpels reduced in number relative to the perianth, or isomerous with the perianth. The pistil 1 celled. Gynoecium syncarpous; synstylovarious; superior. Ovary 1 locular. Gynoecium stylate. Styles 1; apical; short. Stigmas 3 (spreading). Placentation basal. Ovules in the single cavity 1; funicled; pendulous; non-arillate; anatropous; unitegmic (by fusion?); crassinucellate. Embryo-sac development Polygonum-type. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked. Endosperm formation nuclear.
Fruit fleshy to non-fleshy; indehiscent; a drupe (this oblique, more or less compressed, with thin exocarp and bony endocarp). The drupes with one stone. Fruit 1 seeded. Seeds non-endospermic. Embryo well differentiated. Cotyledons 2. Embryo chlorophyllous (1/4).
Physiology, phytochemistry. C3. C3 physiology recorded directly in Pistacia. Not cyanogenic.
Geography, cytology. Holarctic, Paleotropical, and Neotropical. Temperate to tropical. Mediterranean to Afganistan, Eastern Asia, Malaysia, Southeast U.S.A. and Central America.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgrens Superorder Rutiflorae; Sapindales. Cronquists Subclass Rosidae; Sapindales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Sapindales (as a synonym of Anacardiaceae).
Species 10. Genera 1; only genus, Pistacia.
General remarks. The data compiled for this package show Pistacia differing from the related Anacardiaceae sensu stricto (q.v.) in inflorescence, calyx and androecium characters, but floral morphological comparisons are much complicated by dioecism and monoecism.
Illustrations. • Pistacia khinjuk, P. lentiscus, P. terebinthus and P. vera: Nat. Pflanzen fam. III (1896). • Pistacia lentiscus: Bot. Mag. 45 (1817). • Pistacia atlantica: Lindley. • Le Maout and Decaisne: Pistacia.
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: 9th January 2018. delta-intkey.com/angio’.