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..
Lily Family. Scapose or leafy-stemmed herbs from bulbs or corms, or rarely with root-stocks or a woody caudex (Yucca), the leaves various. Flowers solitary or clustered, regular, mostly perfect. Perianth parted into 6 distinct or nearly distinct segments, or these more or less united into a tube, inferior, or partly superior (Aletris). Stamens 6, hypogynous or borne on the perianth or at the bases of its segments; anthers 2-celled, mostly introrse, sometimes extrorse. Ovary 3-celled; ovules few or numerous in each cavity, anatropous or amphitropous; styles united; stigma 3-lobed or capitate. Fruit a loculicidal capsule (septicidal in Calochortus), or in Yucca sometimes fleshy and indehiscent. Embryo in copious endosperm.
About 125 genera and 1300 species, widely distributed.
* Plants bulbous, or with rootstocks, or fibrous-fleshy roots.
+ Ovary superior, not adnate to the perianth.
Low fleshy herb with a short rootstock; flowers white.
Plants with bulbs or corms.
Odor characteristically onion-like: ovules 1 or 2 in each cavity.
Odor not onion-like; ovules several in each cavity.
Perianth funnelform, the tube about as long as the lobes.
Flowers solitary, racemed, corymbed or panicled.
Anthers not introrse.
Perianth-segments all alike or nearly so; capsule loculicidal.
Anthers versatile: tall herbs.
Anthers not versatile; low herbs.
Flowers nodding; perianth-segments with a nectary at the base
Flowers erect; perianth-segments without a nectary.
Leaves only 2, appearing basal; flowers bractless.
Outer segments narrower than the inner; capsule septicidal.
Perianth of 6 separate segments.
Perianth globose, oblong or urn-shaped.
++ Ovary half inferior; roots fibrous; flowers racemed.
** Stem a woody caudex; leaves rigid, mostly bearing marginal fibers.