Lectotype; Lectotype; Herbarium; Herbarium; Herbarium; Herbarium
Original Description
What is Opuntia columbiana?
Opuntia columbiana is a small, cold-hardy prickly pear native to the Columbia Plateau—eastern Washington, eastern Oregon, and possibly adjacent British Columbia. It usually forms low, spreading mats in open, dry sites and can appear variable, with some plants bearing elongate pads and others shorter, more obovate pads. The name has been applied broadly, and some authors regard it as hybrid in origin; see notes below.
Details
There is some uncertainty about the precise nature of the taxon. Possibly, there are two or more taxa that have been interpreted as O. columbiana leading to multiple descriptions. Thus, the paragraph below is our best estimate of a description.
Shrubs: low, mat-forming plants in sparse clumps; growth compact in exposed sites. Cladodes: flattened, narrowly to broadly obovate (sometimes ellipsoid), often fragile; second-year growth may turn yellowish-green. Areoles: small to medium, with conspicuous glochids. Spines: major spines present on most areoles, reflexed to porrect, yellowish to gray-white or brown; commonly (15–)25–40(–50) mm long; radial spines present. Flowers: yellow, about 30–50 mm across; filaments red to brownish-red; anthers yellow; style white; stigma lobes green. Fruits: rarely produced on plants attributed to this name. Seeds: tan, c. 5–7 mm across with a protruding girdle c. 1–1.5 mm wide. Cytology: reported as hexaploid in some material, though the taxon may include more than one lineage.
Range & Habitat
Columbia Plateau of eastern Washington and eastern Oregon, possibly reaching southern British Columbia; usually on dry, open slopes, sandy benches, scabland edges, and other well-drained, rocky to sandy soils in shrub-steppe.
Similar or Sympatric Species
Opuntia polyacantha — larger pads, longer stout spines
Opuntia fragilis — tiny, easily detached pads; low mats
Opuntia polyacantha erinacea — coarse spines, taller clumps
Opuntia cymochila — plains species, broader pads
Other Notes
Some botanists (e.g., Anderson, 2001) have treated this plant as O. × columbiana, a putative hybrid between O. polyacantha (especially var. erinacea) and O. fragilis, suggesting that the name may encompass more than one, not fully stabilized entity. More field and cytological work is needed to resolve its limits.
