Two Erythronium The upper image is a clump of E. revolutum. There is variation in these large clumps and all are self sown seedlings and it is possible  they have hybridized with other species near by. They grow very well in almost full shade and the only disadvantage is when the leaves die down in early summer, and if the tubers are to be maintained in size, they should not be removed until dead and shriveled. 

The lower is Erythronium sibericum. Large and very beautiful. I have two clumps one in a dry sandy bed for raising bulbs from seed and the other planted out in half shade in the peat bed - so very accomodating here.