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.