The families of flowering plants.
Habit and leaf form. Small trees, or shrubs; laticiferous; resinous. Leaves deciduous; alternate; spiral (often densely crowded towards the branch tips); petiolate; non-sheathing; compound; pinnate. Lamina pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins of the leaflets serrate.
Leaf anatomy. Stomata present; anomocytic.
Lamina with secretory cavities (in the phloem). Secretory cavities containing resin, or containing latex; schizogenous. The mesophyll containing calcium oxalate crystals. The mesophyll crystals druses.
Stem anatomy. Secretory cavities present; with resin, or with latex (with thick, milky juice). Cork cambium present; initially superficial. Nodes tri-lacunar. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Xylem with libriform fibres; with vessels. Vessel end-walls simple, or simple and reticulately perforated. Wood parenchyma scanty paratracheal.
Reproductive type, pollination. Plants dioecious. Female flowers without staminodes. Gynoecium of male flowers absent. Floral nectaries absent.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes (female), or in panicles (male). The ultimate inflorescence unit cymose. Inflorescences of female plants consisting of small, 3–4 flowered dichasia, those of male plants in the form of many-flowered panicles; with involucral bracts (female), or without involucral bracts (male); pseudanthial (female plants), or not pseudanthial (male plants). Flowers small; regular; cyclic. Free hypanthium absent. Hypogynous disk absent.
Perianth sepaline (male flowers), or absent (female flowers); of male flowers, 3–8; 1 whorled. Calyx of male flowers, 3–8; 1 whorled; gamosepalous; 3–8 blunt-lobed; regular.
Androecium of male flowers, 3–8. Androecial members free of the perianth; all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 3–8; isomerous with the perianth; alternisepalous. Anthers basifixed (to slightly ventrifixed); versatile; dehiscing via longitudinal slits; extrorse; tetrasporangiate. Pollen shed as single grains. Pollen grains aperturate; (3–)5–8 aperturate; colporate (Juliana), or rugate (Orthopterygium).
Gynoecium 3 carpelled. Carpels reduced in number relative to the perianth. The pistil1 celled. Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary 1 locular; sessile. Gynoecium stylate. Styles 3 (the style tripartite, with flattened branches); partially joined; apical. Stigmas 3. Placentation basal. Ovules in the single cavity 1; ascending; with a placental obturator; hemianatropous; unitegmic; crassinucellate (?).
Fruit non-fleshy; indehiscent; a nut. Gynoecia of adjoining flowers combining to form a multiple fruit (the accrescent, thickened, subglobose involucre containing 1–2 hairy nuts more or less adnate to its wall). Seeds non-endospermic. Cotyledons flat. Embryo curved, or bent (?). The radicle lateral.
Physiology, biochemistry. Not cyanogenic. Alkaloids absent (2 species). Proanthocyanidins present. Ellagic acid absent. Saponins/sapogenins present.
Geography, cytology. Neotropical. Sub-tropical to tropical. Central America, Peru.
Taxonomy.Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rutiflorae; Sapindales. Cronquist’s Subclass Rosidae; Sapindales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Sapindales (as a synonym of Anacardiaceae).
Species 5. Genera 2; Amphipterygium (Juliana), Orthopterygium.