Lily species belonging to the American section are further divided into four categories - American section a, b, c and d. Below are brief descriptions of the various lily species belonging to the four sub-groups of the American sections.
L. bolanderi: This lily species has its origin in southern Oregon as well as northern California. L. bolanderi plants have sturdy stems that bear as many as nine delicate flowers having a true bell form. The color of these flowers varies from brick red to wine red and they have very light crimson or pure red spots on the inner side of the tepals. Flowers of this lily species open in July.
L. columbianum: This American lily species is indigenous to the western regions of North America. The flowers of this species appear in inflorescence, which is a raceme comprising two to ten small, overhanging flowers whose tepals are distinctly reflexed almost mid-way. Subject to the elevation on which the plants grow, the flowers bloom in June, July or even in August.
L. humboldtii: This lily species has its origin in the United States. The plants bear about 10 to 15 flowers in pyramidal inflorescence in June having turk's cap form. The flowers of L. humboldtii have a bright orange color with purple or chestnut brown spots. The pollens of the flowers are deep orange.
L. kelloggii: This lily species is indigenous to the United States and it produces up to 30 flowers in an elevated, pyramidal inflorescence. The tips of these pendant turk's cap flowers are inrolled. The flowers appear in a range of colors including ivory white having pink spots, and turn pink and then magenta as they become mature. Similarly, the pink spots turn wine-red or brown. This lily species blooms in July.
L. rubescens: This lily species also has its origin in the United States' Pacific Coast and each raceme comprises anything between 3 and 30 flowers, which are straight, trumpet-shaped. The tepals of these flowers first form a tube and subsequently, they are also notably reflexed in the last third portion of their length. The flowers of L. rubescens have a white hue when they open, faintly interspersed with purple and gradually their color changes to wine-red or rose-purple. Usually, these flowers bloom in June and July.
L. washingtonianum: This lily has its origin in the mountains of western America. The flowers open in June and July. Each plant bears anything between 2 and 30 horizontal, trumpet-shaped blooms having somewhat reflexed tepals. These flowers have a pure white hue with purplish spots in their throat. These spots turn purple as the flowers age.
L. maritimum: This lily species has its home along the coasts California in the U.S. The flowering stem of this plant may grow up to a height of anything between 10 cm and 200 cm (4 inches and 6 feet), subject to the habitat. The flowers of L. maritimum are small, shaped like bells and their color may vary from deep to delicate orange red. Each stem bears about 1 to 8 flowers.
L. nevadense: This lily species is also known by its common name Nevada biscuit root and it has its origin in the western regions of the United States and northern parts of Mexico. This lily is found growing in a variety of habitats ranging from sagebrush to woodlands. This plant grows up to a height of 45 cm (18 inches) and its white or creamy flowers appear in inflorescence, which is an umbel.
L. occidentale: Native to the Pacific coast in the U.S., the flowering stem of this lily species grows up to a height of anything between 60 cm and 180 cm (2 feet and about 6 feet). This plant bears small egg-shaped leaves that appear in whorls. One flowering stem of L. occidentale produces anything between 1 and 15 small, overhanging, turk's cap shaped flowers having a green base and orange throat, which contains brown spots. The flowers of this lily species bloom in July.
L. pardalinum: This lily species also has its origin in the Pacific Coast of the U.S. The flowering stem of this plant grows up to a height of 120 cm to 200 cm (4 feet to 7 feet). The odourless flowers of L. pardalinum appear on a graceful out-arching stalk. The flowers are strongly reflexed and come in the shape of turk's cap. Each flower measures about 5 cm (2 inches) across. The flowers have a luminous orange-red hue, while their tips are carmine-red. At the center the flowers are marked with strong reddish-brown spots having orange borders. L. pardalinum blooms in July.
L. parryi: This lily species has its origin in the south-western regions of the United States. The flowers of this species have a trumpet shape and are borne horizontally on flowering stalks that grow obliquely upwards. The flowers come in bright yellow color with pale brown spots. This plant grows up to a height of anything between 60 cm and 180 cm (2 feet and 6 feet) and each flower stem bears about 1 to 15 flowers. Sometimes one flower stalk may bear as many as 50 flowers.
L. parvum: This lily species is indigenous to the western parts of the United States. The flower stem of L. parvum grows up to a height of anything between 90 cm and 120 cm (3 feet and 4 feet) and bears small, bell-shaped, out-facing flowers. The flowers come in a variety of colors including orange, yellow and red and have brown spots. Flowers of this lily species bloom in June and July.
L. canadense: This lily species has its origin in the eastern region of North America. The plant bears an umbel comprising as many as 20 flowers, which open in June and July. Generally, the flowers have a yellow hue with deep purple spots. While the flowers appear in the shape of a turk's cap, the tepals are reflexed about mid-way producing a beautiful bell shape.
L. grayi: This American section c lily species is indigenous to Virginia, Tennessee, and North Carolina in the United States. The flower stem of this plant bears anything between 1 and 12 flowers that generally have deep carmine, orange color inside. The flowers are heavily spotted in reddish-purple hue.
L. iridollae: This lily species has its origin in the area extending to the southern region of Alabama and to the north western parts of Florida in south-eastern U.S. The flower stem of this species grows up to a height of anything between 90 cm and 150 cm (3 feet and 5 feet). Typically, the flowers are borne singly, but sometimes a flower stem may bear as many as 8 flowers. The flowers have the form of martagon and are overhanging. The petals are rolled under, while the flowers have a warm, golden-yellow hue. On the lower part, the flowers have numerous brown spots along with the green nectaries. These flowers open during the period between June and July.
L. michauxii: This Lilium species is indigenous to the south-eastern regions of the United States. The inflorescence of this lily species is an umbel comprising one to five potently aromatic, overhanging, turk's cap shaped flowers. The flowers have a luminous orange-red hue, while the throat is yellowish-white.
L. michiganesne: This American section c lily species has its origin in the United States. L. michiganense's flower stem grows up to a height of anything between 60 cm and 150 cm (2 feet and 5 feet). The elliptical leaves of this plant appear in whorls. Each flower stem bears 1 to 8 flowers on elongated, erect flower stem in a slack inflorescence. The flowers are pendant and have an elegant turk's cap shape. They come in red-orange color with plenty of reddish-brown spots at their base. The pollen of these flowers is reddish yellow. The flowers bloom during June and July.
L. superbum: This lily species is indigenous to the eastern regions of the United States. The flower stalk of this plant has a purplish hue and when in cultivation it can be found growing up to a height of 3 meters (10 feet). This lily species bears a pyramid shaped inflorescence comprising as many as 40 large, long-petioled, turk's cap shaped, pendant flowers. The flowers of this lily species come in an orange-yellow hue and their tips are tainted with carmine red. A green star appears in the flower's center, while the throat has several brown spots. The color of L. superbum flowers varies greatly, from a variety of yellow shades and true red. These flowers bloom during the period between July and August.
Lilies belonging to the American section d only comprise two species - Lilium catesbaei and Lilium philadelphicum.
L. catesbaei: This American section d lily species has its origin in south-western United States. The flower stalks of this plant grow up to a height of 30 cm to 50 cm (12 inches to 20 inches). Usually, each flower stalk bears a single flower in an up-facing star-like bowl. The flowers come in yellow or scarlet hues and have several brown spots all over.
L. philadelphicum: This particular lily species is indigenous to North America. Each flower stalk of this plant bears anything between 1 and 5 up facing, extensively opened, bowl shaped flowers that appear in an umbel. The flowers have a vibrant orange-scarlet color and inside the color is deep orange. In addition, in the inner side the flowers often have heavy brown spots.