Flora of North America species comparison

Although the first collection of Douglasia laevigata was from the “Mountains near Mt. Hood,” the original description of the species was based on plants collected in the Columbia River gorge, which thus represent the nomenclaturally typical variety (L. Constance 1938), even though that entity constitutes an ecological variant with almost glabrous leaves and loose umbels known only from the gorge. The widespread form, var. ciliolata, has more compact umbels and larger, more toothed, conspicuously ciliolate leaves. Because intermediate forms occur commonly, and even the type specimen of D. laevigata has cilia, the infraspecific taxa are not recognized here.

A population of Douglasia laevigata from Cone Peak in the Cascade Mountains of Oregon has been reported as heterostylous due to the occurrence of a protruding “pin type” stigma from the corolla throat; this represents only a local stigmatic anomaly functioning as minor spatial separation of anthers and stigma in early anthesis rather than true heterostyly as seen in Primula. No stigmatic or pollen dimorphisms occur in these plants and no parallel “thrum type” flowers are known.

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

Species 9 (9 in the flora).

Whether Douglasia should be considered a separate genus, part of a very broadly construed Androsace, or, perhaps, part of a new segregate genus comprising Androsace sect. Aretia, has been a longstanding question and remains unresolved. Molecular analyses (G. M. Schneeweiss et al. 2004) show a distinct clade that includes the North American and arctic Douglasia species; it is part of a larger primarily European group of Androsace species in sect. Aretia. Although morphologically very similar to those Androsace species, the Douglasia clade differs in chromosome number (chiefly 2n = 38) and shows a large range disjunction between the Alps and the Bering Strait. As currently construed, Androsace in the broad sense covers a broad range of morphologies, especially in the little-studied Asiatic sect. Pseudoprimula, which, morphologically and karyologically, is closer to Primula than to other Androsace; other sections such as the Chamaejasme group show lesser but still significant discontinuities. Additional comprehensive genetic analyses of the entire Androsace complex are needed before it will be possible to assess the appropriateness of segregate or aggregate nomenclature. This treatment follows the current, conventional view in North America of a segregate generic status for Douglasia.

Throughout its range, Douglasia shows a pattern of closely related species with narrow distributions. The species differ primarily in the type and placement of hairs on the vegetative parts; these characters are consistent and reliable markers. Molecular markers (G. M. Schneeweiss et al. 2004) support close relationships but also indicate separate branches that support species-level designations as well as separate clades within Douglasia, where arctic species form one group and those of the continental northwest, from Washington to Montana, another.

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