Flora of North America species comparison

Varieties 7 (7 in the flora).

The variation within Dodecatheon pulchellum is substantial and, for the most part, each of the entities recognized here seems distinct although nearly all break down in one or more features; most seem to have intergraded with other entities in the past. Variety pulchellum is the most widespread and remains, even as treated here, quite variable. The depauperate, often uniflorous, high-elevation form, var. watsonii, is included in var. pulchellum; there is no difference except in overall size even on the East Humboldt and Ruby mountains of northeastern Nevada, the type location of var. watsonii. Widely disjunct populations assigned to var. monanthum remain problematic. The plants of northwestern California and southwestern Oregon differ only slightly from those found elsewhere in Oregon, including the Blue Mountains, where the type of var. monanthum was obtained. The southern Utah expression, while similar morphologically, displays a biogeographic pattern that is unique. A better understanding of the variation between the western and eastern phases of var. monanthum is needed.

The coastal var. macrocarpum has consistent morphological differences and a higher ploidy level (2n = 88, 132) compared with the more inland var. pulchellum (2n = 44). Whether or not the ploidy level difference is consistent remains to be shown.

The arid forms of Dodecatheon pulchellum exhibit remarkable morphological differences that require recognition (J. L. Reveal 2005). Hanging garden plants in Utah are recognized as var. zionense, following N. H. Holmgren (2005). Some populations assigned to this variety may ultimately prove to be merely large-leaved plants of either var. pulchellum or the Utah phase of var. monanthum. Zion shootingstar may owe both its large leaves and its glandular-puberulent pedicels and calyces to hybridization with D. redolens sometime in its evolutionary past, even though the latter taxon is no longer close geographically. Variety shoshonense, usually growing in moist, alkaline meadows, is found mainly in the northern Mojave Desert and the Intermountain West. The color pattern associated with the stamens differs from most other varieties of the species, suggesting a fundamental change associated with pollination and likely a closer relationship to var. cusickii (which also has yellow pollen sacs) than to var. pulchellum.

This taxon inadvertently was named Dodecatheon puberulum (Nuttall) Nuttall three years before the establishment of Exinia pulchella. To avoid nomenclatural disruptions, the basionym D. meadia var. puberulum Nuttall has been proposed for rejection (J. L. Reveal and K. N. Gandhi 2008).

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

Dodecatheon jeffreyi is found in montane places in the Sierra Nevada of California and western Nevada and on the northern coastal ranges and Siskiyou Mountains of northern California and southwestern Oregon. It occurs in the Cascade Ranges of Oregon, Washington, and British Columbia northward to the Kenai Peninsula region of south-central Alaska, often near the coast and especially on the off-shore islands. It is also widely scattered in the mountains of northeastern Oregon, central and northern Idaho, and western Montana, with isolated stations on the Olympic Peninsula of Washington. A single collection (J. Major 2927, GTNP) from Moose Basin, Grand Teton National Park, is the only record from Wyoming.

Dodecatheon jeffreyi is usually readily recognized; in portions of California, the delimitation of it from both D. alpinum and D. redolens can be somewhat arbitrary. Whether this is a breakdown of species boundaries due to hybridization or a shift in their respective morphologies due to overlapping ecological settings is uncertain. In some instances, intermediate plants seem to occur in areas where two of the species occur in proximity. In general, the corolla tube of D. jeffreyi is white except near the ring, where it is yellow. In D. redolens, the entire corolla tube is yellow.

This species is known universally as Dodecatheon jeffreyi, although it was named a year earlier as D. jeffreyanum K. Koch. To avoid the introduction of a name that has never been used for this widespread and sometimes cultivated plant, D. jeffreyanum has been proposed for rejection (J. F. Veldkamp et al. 2008).

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