This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Tall herbs, perennial by rootstocks or tubers, or sometimes annual, with scapose or leafy stems, mostly large entire long-petioled sheathing leaves, often swollen at the base of the blade, the veins pinnate, parallel. Flowers perfect or sometimes polygamous, irregular, in panicles, racemes or spikes. Perianth superior, its segments distinct to the summit of the ovary or united .into a tube, normally in 2 series of 3, the outer (sepals) usually different from the inner (petals). Perfect stamen I; anthers 1-2-celled. Staminodia mostly 5, often petal-like, separate or united by their bases, very irregular. Ovary 1-3-celled, inferior; ovule 1 in each cavity, anatropous; style slender, curved, terminal; stigma simple. Fruit capsular or berry-like, 1-3-celled. Seed solitary in each cavity. Embryo central, in copious endosperm.
About 12 genera and 160 species, mostly in the tropics, a few in warm-temperate regions.