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 bulbous berbs, with simple leafy stems, and large erect or drooping showy flowers. Perianth funnelform or campanulate, deciduous, of 6 separate spreading or recurved segments, each with a nectar-bearing groove at its base within. Stamens 6, mostly shorter than the perianth, hypogynous, slightly attached to the segments; filaments filiform or subulate; anthers linear, versatile, their sacs longitudinally dehiscent. Ovary 3-celled; ovules numerous; style long, somewhat club-shaped above; stigma 3-lobed. Capsule oblong or obovoid, loculicidally dehiscent. Seeds numerous, flat, horizontal, packed in 2 rows in each cavity. [Latin, from the Greek name of the Lily, said to be from the Celtic li, white.]
About 45 species, natives of the north temperate zone. Besides the following, some 8 others occur in western North America. Type species: Lilium cdndidum L.
Flower or flowers erect; perianth-segments narrowed into long claws.
Perianth-segments merely acute.
Leaves lanceolate, nearly all verticillate.
Leaves narrowly linear, nearly all alternate.
Perianth-segments long-acuminate; leaves all alternate, appressed.
Flowers drooping or spreading; perianth-segments not clawed.
Leaves or most of them verticillate, their axils not bulbiferous; native species.
Leaves finely roughened on the veins beneath.
Perianth-segments recurved or spreading.
Perianth-segments not recurved; mountain species.
Leaves perfectly smooth; perianth-segments recurved.
Leaves lanceolate; stem 3°-10° tall; flowers 1-40.
Leaves oblanceolate; stem 2°-3° tall; flowers 1-3.
Leaves alternate, crowded; upper axils bulb-bearing; escaped from gardens.
Lilium philadelphicum L. Sp. PI. Ed. 2, 435. 1762.
Bulb 1' in diameter or less, composed of narrow jointed fleshy scales. Stem 1°-3° tall, with a few distant scales below, leafy above; leaves lanceolate, acute at both ends or the lower sometimes obtuse, 1'-4' long, 3"-7" wide, all verticillate in 3's-8's, or a few of them alternate, thin, the margins finely roughened; flowers 1-5, erect. 2 1/2'-4' high; perianth reddish orange, its segments spatulate, somewhat spreading, acute or obtusish, the blade 1/2-1' wide, rather gradually narrowed into the claw, purple spotted below; capsule obovoid-oval, 1 1/4'-2' high; seeds 3"-4" long, narrowly winged.