Yellow trout lily is an early spring blooming native that grows to 15 cm tall in the partial shade of rich moist woods. It, and a similar Wisconsin species, E. albidum (white trout lily), are easily recognized by extensive patches of lance-shaped leaves with brown or purple mottles. The mottling, which fades on dry specimens, gives the plant its common name since it resembles the underside of a trout. The genus Erythronium has about 15 species, most of which are confined to North America.
Each flowering plant produces a single nodding yellow flower, 2 to 5 cm across. Flowers bloom from mid-April to early May. On sunny days, once the stigmatic surface is receptive, the petals open fully and are recurved. Like most members of the lily family the flowers have 6 tepals (3 petals and 3 sepals), 6 stamens and 3 stigmas. The fruit is a capsule.
Each plant grows from a corm -- an enlaregd portion of the stem that stores starch -- 6 to 10 cm below ground. The leaves are in the middle of the stem, but because the corm is so deep, the leaves may appear basal. The shape of the corm resembles a canine tooth, which led to the name “Dog-tooth violet”.
Trout lilies spread by seed (ant pollinated) and vegetatively by offshoots from the corms. Only plants with 2 leaves produce flowers and most colonies are mostly single leafed plants. Plants from seed take between 4 and 7 years to flower.
Trout lilies retain mineral nitrogen released during snow melt and have low C:N ratios. Like other low C:N plants, they’re preferred by herbivores since they’re easy to digest, and are quickly eradicated when animals such as rabbit or deer become overabundant.
- Origin of the name: Erythronium, erythros, Gr., red, for the red flower color in the type species; americanum, of the Americas
- Range: Eastern US from MN to AK and eastward
- WI Range: In rich woods mostly northern, south to Sauk County, and along Lake Michigan to Racine County
- Common associates: Sugar maple, beech, trillium
- Wetland Indicator Status: UPL
- Coefficient of Conservatism: C = 8 (S&W), C = 5 (MI)