OregonFlora species comparison

Diverse habitat types but most commonly on open slopes, meadows, rocky hillsides. Flowering Feb–Jul. 0–2600 m. BR, BW, Col, CR, ECas, Lava, Owy, Sisk, WV. CA, ID, NV, WA. north to British Columbia, northeast to Alberta, east to CO, southeast to AZ. Native.

Lomatium triternatum is a complex with many ecotypes and morphotypes. Numerous varieties have been named, and some have been delimited at the species level. The ecotypes that have been named include: 1) acaulescent or caulescent plants with pubescent, short narrow apical leaflets lobes (1–4 mm wide) [= L. packardiae]; 2) caulescent plants with short narrow apical leaflets and lobes (1–2 mm wide) that are variously pubescent [= L. tamanitchii; L. triternatum var. brevifolium]; 3) caulescent plants with broad, short leaflets (10–50 × 2–8 mm) [= L. anomalum]; 4) caulescent plants from the west side of the Cascades with very long and broad leaflets (50–120 × 1–12 mm) [= L. triternatum var. macrocarpum]; 5) plants with strictly ternate lateral leaflets with lobes long and narrow (20–90 × 0.4–1.5 mm) and fruit wings (2–3 mm) equal to or wider than the body [= L. simplex]. All of these forms grade into each other imperceptibly, and often more than one form can be found on a herbarium sheet. Although Lesica and Kittlelson (2013) make a robust argu­ment for the separation of L. anomalum from L. triternatum, the condition of the types of L. anomalum prevents the reliable assignment of this name to any of the named ecotypes of L. triternatum. The types are in a mature fruiting stage with dried and withered leaves. Additionally, the leaves are fragmented, and the length and width of the leaflet lobes cannot be determined. The name needs epitypification before it can be applied to forms in the remainder of the range of L. triternatum, regard­less of how other workers have applied this name to specific morphological variants in the past.

Open gravelly or rocky slopes and flats in scrubland and woodland, on igneous-derived substrates. Flowering Mar–Jun. 400–2200 m. BR, BW, ECas, Lava, Owy. CA. Native.

The type publication of Lomatium hendersonii stated that the flowers were white. Mathias did not see the types and retained Coulter and Rose’s interpretation. The types of Leptotaenia leibergii (basionym of L. roseanum) were reported to be yellow-flowered. If it can be confirmed that the types of L. hendersonii were white and that there are extant populations in the John Day River Valley that are white-flowered L. hendersonii, the status of this taxon would need to be re-evaluated. Lomatium hendersonii is found mostly in the mountains of central Oregon, east of the Cascades and southwest of the Wallowas with disjunct outliers in southern Oregon and northern California. The reports from Owyhee County, Idaho, and Washoe County, Nevada, are likely misidentifications of L. roseanum. Lomatium hendersonii is so rarely collected that the characters of the mature fruit are poorly known. More specimens of this taxon in fruiting stage are needed to determine if the wing and body are narrower than those in L. roseanum.