Erythronium is a genus of about 20 species in the Liliaceae family. Most of the species are from Western North America but there are also a few in eastern North America and Eurasia. Dr. Geraldine Allen of the University of Victoria, British Columbia, has been studying Erythronium for many years. She finds that the genus can be divided into two sub-genera, one comprising E. dens-canis, its forms, and the various eastern American species; and one comprising the western erythroniums native to the Pacific Slope of North America. In her view, as a genus, Erythronium is most closely related to Tulipa, an observation that seems almost obvious if you turn an erythronium stem straight up. The Western erythroniums can be split into two groups, those with mottled leaves and those with plain leaves. The ones with mottled leaves are generally considered the most beautiful, and certainly the leaves themselves add greatly to their beauty. Those from foothill woodlands with mottled leaves bloom in the spring and are dormant in the summer. Those from montane meadows and willow thickets have green leaves, summer flowers and are dormant in winter. The Western erythroniums are botanically distinguished by details of the stamens, stigmas, and other sexual organs. Most of the species are quite easy to distinguish.
They are woodland or mountain meadow plants enjoying humus rich but well drained soil. They bloom in the spring. Seeds of western species need to be sown early in the fall for germination. It may take 4 months of longer for some species to germinate. Fresh seed will have a very high germination rate, but seed a year or two old will still perform fairly well if it is sown early enough. Beyond a year or two germination really falls off (Diana Chapman). Seeds of high altitude species need to be stratified before germination will occur. Soaking the seeds overnight in water before sowing has been shown to increase germination. Also, Ian Young (SRGC Bulb Log) has experimented with sowing depth, and has concluded surface sowing (or only barely covered) gives the best results. See Ian Young's Erythronium advice regarding seed here. For more information consult Jane McGary, 2001.
At least one species of Erythronium, E. americanum, has been shown to grow larger bulbs when inoculated with endomycorrhizal fungi, and possibly others as well. An excerpt from a blog post by Travis Owen on Erythronium, March 2016: "A species from Eastern North America, yellow-flowered Erythronium americanum, has been heavily researched. In a handful of studies, mycorrhizal relationships between E. americanum and associated plants were examined. The most exciting discovery, in my opinion, was that bulbs (or as they say, corms) infected with arbuscular mycorrhizal fungi which enter the roots, unlike ectomycorrhiza which don't enter the roots, were found to be nearly twice as large as bulbs treated with fungicide. E. americanum produces roots in the Autumn, as do all Erythronium, and it is then that they are infected. Surrounding plants and trees, such as sugar maple (Acer saccharum) grow in close association with E. americanum and have been found to share mycorrhizae. Another interesting discovery was that E. americanum may help the establishment of young sugar maples by supplying them with carbon through the mycorrhizal network."
"I speculate that other species of Erythronium also participate in mycorrhizal networks, and that they benefit from the infection as well. Many of the trees and shrubs that grow in association with Erythronium hendersonii and E. oregonum, for example, benefit from or require mycorrhizae (Acer sp., Arbutus menziesii, Arctostaphylos viscida, Ceanothus sp., Quercus sp., Pseudotsuga menziesii, etc.), therefore it is not inconceivable that they too benefit from mycorrhizal associations."
Many of the Western North American species of Erythronium were first collected and described by Elmer Ivan Applegate (March 31, 1867 – November 16, 1949). Though many of his names are no longer considered valid, he was still very important to this genus. The Native Plant Society of Oregon (NPSO) newsletter, Kalmiopsis, published a good biography of his life and influence of the discovery of many taxa written by Frank A. Lang, as well as more interesting information on species native to Oregon. Read it here.
Ed Alverson, a botanist from Oregon, wrote an article about his travels to California's endemic populations of various erythroniums for the SRGC. Read the article here.