Home

The families of flowering plants.                                                                                                                                                                

~Grossulariaceae

ExcludingPterostemonaceae

Habit and leaf form. Trees, or shrubs. Plants non-succulent. Leaves evergreen, or deciduous; alternate; ‘herbaceous’, or leathery (sometimes holly-like); petiolate; non-sheathing; simple. Lamina entire. Leaves stipulate. Lamina margins serrate, or dentate (or spinose).

Leaf anatomy. Minor leaf veins without phloem transfer cells (Itea).

Stem anatomy. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent.

Reproductive type, pollination. Plants hermaphrodite, or polygamomonoecious.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in panicles. The ultimate inflorescence unit cymose. Inflorescences terminal, or axillary; densely elongate-racemiform or shortly cymose. Flowers small; fragrant; regular; 5 merous; cyclic; tetracyclic. Free hypanthium present (as a turbinate ‘calyx tube’). Hypogynous disk (or perigynous disk) present; intrastaminal; annular.

Perianthwith distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; polysepalous (on the hypanthium); regular; persistent; valvate, or open in bud. Corolla 5; 1 whorled; polypetalous (the petals narrow); valvate; regular; white.

Androecium 5. Androecial members free of the perianth; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 5; isomerous with the perianth; oppositisepalous (?); filantherous (the filaments subulate). Anthers dorsifixed; non-versatile; dehiscing via longitudinal slits; introrse (oblong or ovate). Pollen grains aperturate; 2(–3) aperturate; porate.

Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth. The pistil2 celled. Gynoecium syncarpous; synovarious, or eu-syncarpous (the two connate styles finally becoming free, or remainong united by the capitate stigma); superior to partly inferior. Ovary2 locular. Gynoecium stylate. Styles 2; free, or partially joined (initially connate, subsequently free or remaining joined only by the stigma); apical. Placentation axile. Ovules 4–50 per locule (‘few to many’); usually biseriate.

Fruit non-fleshy; dehiscent; a capsule (narrow or ovoid). Capsules septicidal.Seeds sparsely endospermic. Endosperm fleshy. Seeds flattened, oblong or scobiform. Embryo well differentiated (large). Micropyle not zigzag.

Physiology, biochemistry. Cyanogenic. Cynogenic constituents tyrosine-derived (triglochinin?). Proanthocyanidins present; delphinidin. Flavonols absent. Ellagic acid absent (Itea).

Geography, cytology. Holarctic, Paleotropical, and Cape. Temperate to tropical. East and Southeast Asia, eastern North America, tropical and South Africa.

Taxonomy.Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rosiflorae; Cunoniales. Cronquist’s Subclass Rosidae; Rosales. APG 3 core angiosperms; core eudicot; unplaced at Superordinal level; Order Saxifragales.

Species 17. Genera 2; Itea, Choristylis.

General remarks. Bohmet al. (1988) provide details of Itea flavonoids.