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..
Leafy-stemmed herbs (some exotic genera scapose), with rootstocks or rarely with bulbs, the leaves broad or grass-like, parallel-veined, the veins often connected by transverse veinlets. Flowers perfect, polygamous, or dioecious, regular, racemose, panicled or solitary. Perianth of 6 separate or nearly separate, usually persistent segments. Stamens 6, borne on the bases of the perianth-segments. Anthers small, 2-celled, oblong or ovate, or confluently 1-celled and cordate or reniform, mostly versatile and extrorsely dehiscent (introrse in Tofieldia, Triantha and Abama). Ovary 3-celled, superior or rarely partly inferior; ovules few or numerous in each cavity, anatropous or amphitropous. Styles 3, distinct or nearly so. Fruit a capsule with septicidal dehiscence (loculicidal in Abama). Seeds commonly tailed or appendaged. Embryo small, in usually copious endosperm.
About 40 genera and 145 species, widely distributed.
Anthers oblong or ovate, 2-celled.
Anthers introrsely dehiscent.
Capsule septicidal; flowers involucrate by 3 bractlets.
Inflorescence centripetal; seeds unappendaged.
Inflorescence centrifugal; seeds appendaged.
Capsule loculicidal: flowers not involucrate.
Anthers extrorsely dehiscent.
Leaves basal, oblanceolate; seeds numerous.
Stem very leafy; leaves linear; seeds few.
Flowers dioecious; stem leafy.
Anthers cordate or reniform, confluently 1-celled.
Perianth-segments not gland-bearing.
Flowers perfect; perianth-segments obtuse.
Flowers polygamous; perianth-segments acuminate.
Perianth-segments bearing 1 or 2 glands, or a spot.
Plant with a thick horizontal rootstock; perianth-segments with 2 glands.
Plants bulbous, or with short erect rootstocks; perianth-segments with 1 gland.
Flowers perfect; bulbs membranous-coated.
Ovary partly inferior; gland obcordate.
Ovary wholly superior; gland obovate or half-orbicular.
Flowers polygamous; rootstocks fibrous-coated.
Stem and inflorescence pubescent.
Perianth-segments distinctly clawed, glandless.
Perianth-segments not clawed or very short-clawed, 2-glandular.