L. michiganense and L. superbum and are very similar perennial forbs. These tall lilies are identified by the backward curving tepals. This completely reveals the stamens and the pollen. The details here are for Michigan Lily
The stems are smooth, round and green, unbranched below the inflorescence. Height can reach 5 to 7 feet.
Leaves form evenly distributed whorls on the stem and are alternate on the upper side branches. Leaves are lanceolate in shape, with smooth edges and parallel veins. They can be 4 to 18x longer than wide, are held horizontally, with the upper whorls upward ascending, and then drooping at the pointed tips. Surfaces are without hair but the lower leaf surfaces along the veins and margins tend to be somewhat rough. There are 4 to 12 whorls of leaves with 3 to 13 leaves per whorl, 3 to 7 being typical. Old mature plants will have the most leaves per whorl as will plants in more sunny and moist areas.
The inflorescence consists of long stalked flowers, appearing as singles on in an umbel of 2 or 3, branching from the top of the stem and the upper leaf axils with a total of 1 to 11 flowers; flower buds are rounded in cross-section; occasionally a plant can produce many more flowers.
The flowers are pendant and not fragrant. The 3 sepals and 3 petals look the same (commonly called 'tepals') and as the flower opens they flare outward and then reflex with the tips usually not touching; these are yellowish orange near the base and then shade to reddish orange. The outer 3 are not ridged on the back side. The nectaries at the base of the tepals are less noticeable in L. michiganense as the tepals do not reflex as far as on L. superbum. The tepals have darker colored maroon speckles. There are 6 stamens, strongly exserted beyond the tepals with anthers up to 1/2 inch long, light magenta in color. The filaments diverge and spread close to their bases. The single style, is red or at least red or reddish near the tip.
Seed: Curiously, when the seed head forms, it will turn upward as it matures. Inside are hundreds of wafer thin disc shaped seeds. These are hard to start as they must have a warm moist period followed by a cold moist period before planting. Sown outside they will germinate in the next year. Pollination is primarily by swallowtail butterflies.
Habitat: These plants are becoming uncommon in the wild due to cultivation and roadside mowing. Like most lilies the plants grow from a bulb with offsetting rhizomes. The bulb is more whitish-yellow and the rhizomes do not branch. L. michiganense prefers prairies, ditches, and woodland edges where it gets more sun but with wet to mesic moisture conditions.
Names: The genus Lilium is derived from the Greek word 'lirion' for lily. The species name michiganense means 'of Michigan.' The accepted author of the plant classification - ‘Farw.’, refers to Oliver Atkins Farwell (1867-1944) American Botanist, largely self-taught in botany, he taught school for a few years, then became curator and librarian of the herbarium at Parke, Davis and Company, a drug firm, where he was in charge of pharmacognosy of raw botanical product. His papers are Michigan Technological University.
Comparisons: There are several other lilies that have reflexed petals and sepals of this color range. The ones most often confused are first -the Tiger Lily, Lilium lancifolium. There the most easily distinguishing characteristics are lanceolate shaped leaves that are alternate, not in a whorl and the presence of dark bulbils in the leaf axils on the stem. The closest confusing relative is the Turk's-cap Lily, L. superbum. It is usually taller, has more flowers in the inflorescence, up to 22, with buds that are triangular in cross-section. It has more leaf whorls (6 to 24) with 3 to 20 leaves per whorl. In the flower, the tepals reflex more revealing the nectaries at the base of the tepals - it looks like a green star. It has a whitish bulb with rhizomes that branch, but grows in similar habitat. Another close relative (and so close that it has been proposed that the two are varieties of the one species) is the Canada Lily, L. canadense. If the tepals of Michigan Lily do not reflex fully, it could be mistaken for the The Canada. It is known that they interbreed.
Above: A grouping of Michigan Lily in Early July.
Below: 1st photo - The tepals of Michigan Lily, L. michiganense, are yellow-orange near their base without the green star-like base of L. superbum (2nd photo) and the stamens spread further and begin spreading nearer the base of the filaments.
Below: Leaf whorls of large mature plants - lower whorls have more leaves. 1st photo - Michigan Lily, 2nd photo - Turk's-cap Lily which has more leaves per whorl.
Below: 1st photo - The upward turned seed heads of late fall. They will remain throughout the winter if the stalk is not blown down. 2nd photo - Each seed pod has several stacked vertical rows of wafer thin seeds. [the more triangular capsules of Turk's-cap Lily are shown here.]
Below: The tepals have dark maroon spots, the outer 3 do not have ridges on the back side and the style is reddish.
Below: - The bulb of Michigan Lily with two newer offsets.
Notes: L. michiganense is indigenous to the area around the Garden, but was not originally found in the Garden. Curator Martha Crone planted it in the Garden in June 1946 (and also L. superbum). L. michiganense is native to most counties in the eastern half of Minnesota and a few further west in the west-central part of the state. It has been replanted as recently as 2012 by Curator Susan Wilkins, who also added L. superbum in 2009.
Only two lily species are native to Minnesota: L. michiganense, Michigan Lily; and L. philadelphicum, Wood Lily.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"