Flora of North America species comparison

Subspecies 2 (2 in the flora).

Lilium humboldtii is declining throughout its range due to habitat destruction, primarily for housing. Forming large scattered colonies at foothill elevations under ponderosa pines or in oak canyons and chaparral, these massive plants with towering inflorescences and large flowers are quite striking. With Lilium pardalinum and L. parryi, they were used in the early part of the century to produce the Bellingham hybrid lilies, development of which continued with the Bellmaid hybrids. Though not as popular as various Asiatic hybrids, these are still in use.

A. M. Kellogg was aware as early as 1859 that the tall, orange-flowered, dry-land lily from the foothills of the Sierra Nevada was distinctive, and he presented this opinion to the California Academy of Sciences about that time (A. M. Kellogg 1872). By the time he had published a description attached to the name Lilium bloomerianum, P. E. S. Duchartre had described this same plant from material provided by B. Roezl and grown by M. Leichtlin, and named it after the German explorer and botanist Alexander von Humboldt. Carl Purdy and others then misapplied Kellogg’s name in various combinations to the southern California expression recognized here as Lilium humboldtii subsp. ocellatum.

The Humboldt lily is pollinated primarily by large butterflies, especially western tiger swallowtails (Papilio rutulus Lucas, family Papilionidae) and pale swallowtails (P. eurymedon Lucas), and to a lesser extent by the monarch butterfly [Danaus plexippus (Linnaeus), family Nymphalidae].

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

Of conservation concern.

In the late nineteenth century, botanist and bulb merchant Carl Purdy employed Native Americans to collect bulbs of lilies and other desirable plants in the area around Eureka, California, and Lilium occidentale was among the species he was brought. After Purdy described Lilium occidentale in 1897, the plant came into great demand. He later (C. Purdy 1937) lamented that almost no plants were available for cultivation. Populations fluctuated in the middle of the twentieth century and frequently declined dramatically from overcollecting following publicity that the plants had recovered and flowered. Much habitat was subsequently lost to ecological succession and land conversion. Fortunately, several large populations have recently been discovered near Crescent City, California, and completion of a recovery plan (Fish and Wildlife Service 1998) bodes well for the future of this state and federally protected plant.

Lilium occidentale occurs in scattered populations from Humboldt Bay, California, to Coos Bay, Oregon, always within six kilometers of the ocean. Plants near Humboldt Bay occur in coastal prairies and scrub, whereas many Oregon populations are found in sphagnum bogs. Typical Oregon and extreme northern California plants in the vicinity of Crescent City (Del Norte County) have an irregular bulb that occasionally is nearly erect (0.3–0.7 times taller than long versus 0.3–0.5 in Humboldt Bay plants). In northern plants the leaves are often scattered—though they are whorled in larger plants—and extremely long and thin [4.2–26.3 × 0.4–2.7 cm (4.6–28.6 times longer than wide) versus blade 4.1–18.9 × 0.7–3 cm (4–17.4 times longer than wide)] in Humboldt Bay plants. Flowers of Oregon plants are marginally smaller, have somewhat narrower sepals (4.4–7.6 × 0.8–1.5 cm) than Humboldt Bay plants (4.4–8.1 × 1–1.8 cm), and typically appear somewhat later. These differences have provoked discussion about the merits of subdividing this species, but many of the differences appear to be related to habitat rather than genotype. For example, plants from Shores Acres State Park in Coos County, Oregon, occur in a coastal bluff setting that is similar to habitats near Humboldt Bay, and these lilies share many of the same vegetative and floral characteristics of Humboldt Bay plants. Subspecific differentiation appears to be unwarranted.

Lilium occidentale is distinguished from similar species such as L. pardalinum by the closely parallel stamens and adaxial green star formed by the conspicuously green sepal and petal bases, a characteristic also discernible in the abaxial surface of the buds. This green star is present in nearly all flowers when first opened, but changes to yellow or yellow-orange as the flowers age. The green star of certain eastern taxa (e.g., L. superbum) is also diagnostic for them but is primarily formed by glossy green adaxial nectaries and is not so prominent in bud.

Frequent hybrids with Lilium columbianum in Oregon occur primarily where human disturbance has introduced that species into boggy areas via drier open pathways such as powerline right of ways and roads.

With the likely exception of Lilium canadense, L. occidentale is the only North American pendent lily that is pollinated almost exclusively by hummingbirds (in California primarily the Allen’s hummingbird [Selasphorus sassin (Lesson), family Trochilidae]). Its pendent red flower is transitional between butterfly-pollinated forms like L. pardalinum and the classical bird-adapted flowers of L. maritimum and L. bolanderi that are more tubular and horizontal.

The Karok ate Lilium occidentale bulbs after baking them in an earth oven (D. E. Moerman 1986).

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