COMMELINACEAE (Spiderwort Family)
Plants annual or perennial herbs, the roots
sometimes thickened and fleshy or tuberlike. Stems usually branched, sometimes
somewhat succulent. Leaves alternate, herbaceous or sometimes slightly
succulent, often folded longitudinally, the bases forming tubular sheaths.
Veins parallel, a pronounced midvein usually present. Inflorescences terminal
and/or axillary clusters of flowers, these subtended by folded, leaflike or
spathelike bracts. Flowers perfect, radially or bilaterally symmetric. Sepals
3, free, herbaceous, green. Petals 3, usually free, variously colored,
sometimes 1 petal different in size and shape than the other 2. Stamens 6 or if
only 3 then 2 or 3 staminodes also present, usually free. Ovary 1 per flower,
superior, with 2B3 locules. Style and stigma 1, the stigma
usually capitate. Fruits capsules, with 3B9, small, circular to oblong, flattened seeds.
About 50 genera, 600B700 species, nearly worldwide, but mostly
tropical to subtropical.
The petals of most members of the Commelinaceae
are very ephemeral, lasting only part of a day and wilting (along with the
foliage) practically immediately if the stems are picked. The perianth parts of
pressed flowers also either become distorted during drying or adhere to the
pressing papers and are lost. The species are therefore most easily keyed while
still fresh, and particularly such structures as the minutely gland-tipped
hairs of some Tradescantia species are much more easily noted in living