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 narrowly endemic Gray’s lily blooms predictably on or about July 4 in the balds and forest openings of the Roan Mountain massif shared by North Carolina and Tennessee. In its unadulterated form it also occupies the higher elevations of the Blue Ridge Mountains, including Grandfather Mountain in North Carolina and Mount Rogers and Whitetop Mountain in Virginia. A few populations occur at lower elevations (below 900 m) in streamside meadows along the Blue Ridge Parkway in northern North Carolina (Alleghany County), but in similar settings farther north in Virginia introgression with L. canadense occurs.

Lilium ×pseudograyi Grove (as species) is a name given to frequent hybrids between L. grayi and L. canadense that are scattered at somewhat lower elevations (usually 700–1000 m) in the southern Appalachians. The generally small stature of these hybrids is misleading and encourages the label of bona fide L. grayi, but in most respects they are intermediate. Sepal lengths of 4.8–6.2 cm and floral tube lengths of 3.2–4 cm predominate, and these are between the ranges of the two parent species. The freshwater wetland or moist hardwood habitat of these hybrids also reveals the contribution of L. canadense to their genome.

J. K. Small (1933) made reference to depredations by lily enthusiasts who sought Gray’s lily because of its supposed rarity, and this continues today, though to a lesser degree. Of greater threat, perhaps, is succession on the high grassy balds that gradually shades and crowds the plants; like most lilies, this one requires open conditions for vigor and reproduction.

Although fritillaries (Speyeria spp., family Nymphalidae) pilfer nectar from flowers of Gray’s lily, ruby-throated hummingbirds [Archilochus colubris (Linnaeus), family Trochilidae] are its only reliable pollinator. This red, tubular-flowered lily represents the zenith of pollinator-mediated evolution in the eastern true lilies, and is a high-elevation derivative of the ancestral stock that also produced Lilium canadense. The level of floral convergence with independently derived western Lilium species such as L. bolanderi and L. maritimum is remarkable and must be due to selection pressures exerted by hummingbirds during the floral evolution of these species.

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