Lilium is a large genus in the Liliaceae family. Information and pictures of species on the PBS wiki are found on section pages. This wiki page is for the Trumpet Section. Other sections and hybrids are linked below.
American Section A-M - American Section N-Z – Asiatic Section – Candidum Section - Dauricum Section – Martagon Section – Oriental Section - Lilium Hybrids - Lilium index
Lilium formosanum, nominate form. Plants in cultivation at the Strybing Arboretum, Golden Gate Park, San Francisco, CA. Photo by Ron Parsons.
Lilium formosanum var. pricei - This is a dwarf form of the much taller Formosa Lily. The taller 'type' species is sometimes considered weedy because it seeds about too readily. This short variety grows 12"-18" (30-45 cm) tall, is reliably hardy even in northern New England, but seems to be short-lived, lasting 2-3 years then dying out, but not to worry, typically a few seedlings show up. Here are two views showing a rougue seedling that got into my bed of Allium flavum ssp. tauricum color forms. The flowers are richly colored on the back, pristine white within, and powerfully sweet scented. Photos by Mark McDonough.
Lilium leucanthum from Sichuan China. These plants were growing in the UC Berkeley Arboretum, photos by Ron Parsons.
Lilium leucanthum var. centifolium from China. This variety is from W. Gansu and can grow to 10 feet tall. Here it is grown in New Jersey, photos by Arnold Trachtenberg.
Lilium longiflorum is the ever popular "Easter lily" which has been highly hybridized. This one was set behind the apple tree several years ago and forgotten. There are three stalks and nine flowers all open at the same time. Grown in Long Beach, CA by Doug Westfall.
Lilium regale native to Sichuan, China. Photo of plant in cultivation at the UC Berkeley Arboretum by Ron Parsons.
Lilium sargentiae grows to 1.5 metres tall, with funnel-shaped, fragrant flowers. This location is further south-west than those normally cited, which are in Sichuan. The first photo, by David Victor, was taken near the Liang Jang (Mekong) river, Yunnan, China. The other photos, by Arnold Trachtenberg, are of a bulb from a Chinese grower, Chen Yi.
Lilium sulphureum is late blooming trumpet lily having a soft yellow glow from within. Note the long flower. It came into bloom the first week of August and had abundant stem bulbils. Here in the middle Atlantic states of the US, other trumpet lilies typically bloom from the last week of June through the first two weeks of July. First photo by Jim McKenney of a plant grown by Debby Sheuchenko in central Virginia from material received from Chen Yi. Other photos, taken September 2004 by Lee Poulsen, have greener flowers than Jim's plant.
Lilium wallichianum is a white stoloniferous species from the Himalayan region (India, Nepal, Bhutan, Sikkim) where it is found on limestone slopes in open coniferous forests. Photo by Ron Parsons. 
American Section A-M - American Section N-Z – Asiatic Section – Candidum Section - Dauricum Section – Martagon Section – Oriental Section - Lilium Hybrids - Lilium index