GERANIACEAE (geranium family)

Plants annual or perennial herbs (shrubs elsewhere), often with glandular pubescence. Stems often with somewhat swollen nodes. Leaves basal and alternate or opposite, long-petiolate to nearly sessile. Stipules herbaceous, sometimes appearing scalelike, lanceolate to ovate or ovate-triangular. Leaf blades simple or compound, pinnately or more commonly palmately veined and divided or lobed, the margins usually toothed. Inflorescences axillary and often also terminal, small panicles or loose clusters, these sometimes umbellate, sometimes reduced to solitary flowers. Flowers actinomorphic (somewhat zygomorphic elsewhere), perfect, hypogynous. Calyces of 5 free sepals. Corollas of 5 free petals, usually alternating with minute nectaries at the base. Stamens 5 or 10, the filaments free or fused at the base, narrowly winged or expanded toward the base, the anthers attached toward their midpoints, bluish purple (appearing yellow as the pollen is released). Staminodes present in 5-stamened species, appearing as narrow scales similar to the filaments of fertile stamens but often somewhat shorter. Ovary 1 per flower, superior, of 5 fused carpels fused to a slender central column (this persistent, becoming elongated as the fruits mature), 5-lobed toward the tip, with 5 locules. Styles 5, but fused to the beaklike central column for most of their length, persistent and becoming elongated at fruiting, the stigmas 5, club-shaped or linear. Ovules 2 per locule. Fruits schizocarps, 5-lobed toward the base, splitting from the column into 5 mericarps at maturity, each with 1 seed, the stylar beak persistent on each mericarp. About 11 genera, about 700 species, nearly worldwide but most diverse in temperate or montane tropical regions.

Members of the genus Pelargonium L’Hér. are widely cultivated for their attractive flowers and foliage, mostly as indoor plants in homes and conservatories. They are the familiar geraniums of horticulture and belong to a genus of about 280 species native mostly to Africa. Pelargonium differs from the closely related Geranium in its zygomorphic flowers and contains species with a bewildering variety of different morphologies, including shrubs, succulents, and tuberous or spiny plants.