Flora of North America species comparison

Subspecies 5 (5 in the flora).

The subspecies of Lilium pardalinum display a classic pattern of discrete geographical ranges with intervening zones of introgression, and no two occur sympatrically without intermixing. Plants in the hybrid zones are confusing in appearance and cannot be assigned to subspecies. However, each subspecies is fairly well marked within its core distribution. With the exception of subsp. pitkinense, the subspecies of L. pardalinum can be common plants in the proper habitats within their rather narrow distributions.

Leaf size and shape are quite variable in Lilium pardalinum subspecies and often clearly dependent on environment. In populations that typically have narrow, ascending leaves, shaded plants often have wide, horizontal leaves. This hampers taxonomic separation as well as identification, especially of herbarium specimens. Further field study is desirable.

Lilium pardalinum is primarily pollinated by western tiger swallowtails (Papilio rutulus Lucas, family Papilionidae) and pale swallowtails (P. eurymedon Lucas); several species of hummingbirds (family Trochilidae) are also important visitors, especially when butterflies are rare.

The Atsugewi, Karok, and Yana ate Lilium pardalinum bulbs steamed or baked in an earth oven (D. E. Moerman 1986).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

The largest Lilium east of the Rocky Mountains and the commonest over most of its range, the Turk’s-cap lily is a familiar sight throughout much of the southern Appalachians and along the northern Atlantic coastal plain. Flowers are rather variable; those in the north are sometimes floridly colored with dark purple bases on the perianth parts. The single report from Vermont (F. C. Seymour 1993) remains unconfirmed; however, recent collections from Washington Parish in Louisiana, Perry County in Missouri, and Bamberg County in the coastal plain of South Carolina extend the range of this species.

Lilium superbum shares distinctive features with L. michauxii, L. pyrophilum, and L. iridollae that indicate a close relationship and are diagnostically useful, namely paired ridges on the backs of the sepals and buds that are triangular in cross section. None has the red style characteristic of the other eastern pendent lily clade (L. michiganense, L. canadense, and L. grayi) centered to the northwest, and only L. iridollae sometimes has the leaf margins and veins roughened abaxially as is characteristic of L. canadense and its close relatives.

Common inheritance of a suite of unique, derived features and peripheral allopatric distributions suggest that Lilium pyrophilum and L. iridollae may be geographical isolates of broadly distributed L. superbum ancestral stock; both restricted species occur in specialized wetland habitats. Geography aside, the three are unequivocally distinguished only by various combinations of leaf and bulb characteristics, flower color, habitat, and blooming time. However, the overall degree of separation is comparable to that between many other species in the genus. Lilium superbum blooms the earliest, is the largest, and has the most numerous and largest flowers, and the long, narrow leaves in many whorls are distinctive. Lilium michauxii overlaps in range with these three species but is easily separated morphologically and ecologically.

Lilium superbum is pollinated primarily by the swallowtail butterflies that are common within its range, among them the spicebush (Papilio troilus Linnaeus, family Papilionidae), pipevine (Battus philenor Linnaeus), and eastern tiger (Papilio glaucus Linnaeus). Great spangled fritillaries [Speyeria cybele (Fabricius), family Nymphalidae] also visit the Turk’s-cap lily (R. M. Adams and W. J. Dress 1982).

(Discussion copyrighted by Flora of North America; reprinted with permission.)