Flora of North America species comparison

Dodecatheon hendersonii occurs from southern Vancouver Island in the coastal ranges to west-central California (as far as San Benito County) and is disjunct into the San Bernardino Mountains in southern California. To the east, the species is found on the Siskiyou Mountains and in the Sierra Nevada of California to Tulare County. A Macoun (s.n., DAO) specimen supposedly gathered at Yale, British Columbia, may be misattributed (K. I. Beamish 1955); all other known localities are from Vancouver Island.

Inasmuch as bulblets and mature capsules are rarely collected, it is difficult to clearly distinguish between var. hendersonii and var. hansenii. The former may be broadly characterized as plants bearing bulblets at anthesis with sparsely glandular scapes, pedicels, and, sometimes, calyces. The calyx of var. hendersonii is usually greenish with purple or reddish speckles. The most distinctive characteristics of this phase are a filament tube that is 1–2.5 mm wide and acute anther apices. It is found mainly along the coast from British Columbia to southern Oregon and in scattered locations in coastal California, with disjunct populations in the foothills of the central Sierra Nevada, and in the mountains of southern California. Variety hansenii is glabrous, lacks bulblets, and the calyx typically is green; it usually is found inland in the Siskiyou Mountains and the Sierra Nevada and scattered populations occur in the coastal ranges of northern California. The filaments in var. hansenii are broader, being tubes 1.5–4 mm wide, and anther apices are obtuse. Capsules of var. hendersonii are usually operculate; those of var. hansenii appear to be consistently valvate. The 2n = 66 plants appear to be primarily individuals that produce little or no pollen.

Adding to the complexity is the close association of var. hansenii with Dodecatheon clevelandii var. patulum. The latter, like var. hendersonii, is basically a diploid or a tetraploid (2n = 44, 88), rather than a hexaploid, and one would expect no crossing between the two. Nonetheless, H. J. Thompson (1953) reported finding sterile individuals where D. hendersonii var. hansenii and D. clevelandii var. patulum were in close association. These sterile individuals were morphologically similar to var. hansenii (and not intermediate between the two), and sterile individuals were fairly common in populations of var. hansenii where no other Dodecatheon were present. Although the three entities may be characterized (see table 5 in Thompson), Thompson concluded that assigning names to some populations was difficult and could be established “only by a detailed consideration and summation of all the characters.”

H. J. Thompson (1953) recognized Dodecatheon hansenii; A. F. Cholewa and D. M. Henderson (1993) accepted only D. hendersonii. In their molecular study, A. R. Mast et al. (2004) considered the two entities distinct, albeit closely related, species. It is possible that var. hansenii had a hybrid origin involving var. hendersonii and D. clevelandii var. patulum, and backcrossing with var. hendersonii resulting in a series of morphological features that allies the hansenii phase more to D. hendersonii than to D. clevelandii. More study is needed, especially in areas where the two appear to have overlapping ranges in the Bay Area and Sierra Nevada foothills of California.

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

Dodecatheon alpinum is found in widely scattered locations in the San Jacinto Mountains, Transverse Ranges, Sierra Nevada, northern coastal ranges, and the Siskiyou Mountains of California, southwestern Oregon, and west-central Nevada, and in the Cascade Ranges to just north of the Columbia River in Skamania and Yakima counties of Washington. It may be seen on scattered basin ranges in the Intermountain West of Nevada (e.g., East Humboldt, Jarbidge, Ruby, Snake) and western Utah (Deep Creek Mountains), and in some desert ranges of southern Oregon as far east as the Steens Mountains in Harney County; it is disjunct to the Blue and Wallowa mountains of northeastern Oregon. There are other disjunct populations in the northern Wasatch and Uinta mountains of northern and northeastern Utah, and even more widely scattered populations in the southern Wasatch and Tushar mountains. The species has also been found at Warm Springs in Millard County. Isolated populations occur on the Pine Valley Mountains, Utah, and around the Grand Canyon and Mogollon Rim areas of Arizona as far south as Greenlee County.

Narrow-leaved plants that are sparsely glandular-pubescent are sometimes found at higher elevations in the Sierra Nevada, making a distinction between Dodecatheon alpinum and D. jeffreyi occasionally arbitrary. A specimen from Deschutes County, Oregon (C. L. Hitchcock and J. S. Martin 4919, UTC, WTU) has leaf blades to 3.5 cm wide.

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