The genus Erythronium has been in cultivation for many centuries. One of the reasons its supply remains so scarce is due to its difficult cultivation. Tubers of Erythronium are very sensitive to wind and partly because of this, the bulbs can dry out quickly after lifting. Harvesting by machine is not good for quality; damage to the tuber quickly leads to mildew. It is widely distributed in central and southern Europe, Iran and the Caucasus and many species originate in North America. The hybrids, created from crosses of E. tuolumnense x E. revolutum, are of Dutch origin (including from Mr L. Slikker). The name dog-tooth is derived from the fused tubular bulb, which is similar to a dog's tooth. The leaves are opposite and broadly oval-shaped, always two per plant. Almost all erythroniums have brilliantly marked leaves. A notable detail is that except for many species that have nodding flowers, the tips of the petals are bent backwards as flowering progresses. The plants like a somewhat sandy humus-rich soil in a shady spot and the bulbs should be planted quite deep. They can stand in the same place for many years and reproduce mainly by seed.