Turner (1992) described the mitotic and meiotic chromosomes of four Oregon Delphinium species: D. trolliifolium, D. menziesii, D. pavonaceum and D. leucophaeum, for taxonomic comparison. Initial examination of chloroplast genetic variation within a population of Delphinium pavonaceum known to have color and chloroplast variation did not reveal the source of color variation or give insight to any past hybridization event (Mazer 2000).

Urban expansion (Meinke 1982) Agricultural development (Meinke 1982) Herbicides (both agricultural and roadside) (Meinke 1982) Woody plant encroachment (Finley and Ingersoll 1994) Hybridization with a purple-flowered Delphinium (Karoly personal c

Historically, 35 occurrences known in Benton, Polk, Marion, Multnomah, and Clackamas counties. Only 18 occurrences have been seen since 1980. Population sizes range from as little as 1 to as many as 2000. Most have between 10 and 100 (ONHDB 2000).

Comprehensive study of systematics, morphology, distribution, ecology, and reproductive dynamics (Goodrich 1983). A 1994 field survey found that populations varied in size from 3 to more than 2000 flowering individuals. Roadside plants appeared to be immanently threatened by the invasion of reed canary grass (Phalaris arundinacea) and other roadside weeds. Other sites appeared to be threatened by encroaching canopy of trees and tall shrubs (Finley and Ingersoll 1994) Observations indicated no evidence of hybridization with blue-flowered Delphinium menziesii where the two flowers co-occurred (Finley and Ingersoll 1994). Comparison between plants found in burned and unburned areas of a Research Natural Area (RNA) found that abundance, growth and reproduction was higher in burned areas. These observations are consistent with the hypothesis that frequent burning enhances growth and reproduction, but researchers note other factors that could contribute to the difference including a moisture gradient between the two areas (Finley and Ingersoll 1994). Turner (1992) described the mitotic and meiotic chromosomes of four Oregon Delphinium species: D. trolliifolium, D. menziesii, D. pavonaceum and D. leucophaeum, for taxonomic comparison. Initial examination of chloroplast genetic variation within a population of Delphinium pavonaceum known to have color and chloroplast variation did not reveal the source of color variation or give insight to any past hybridization event (Mazer 2000). Germination trials at The Berry Botanic Garden indicate that a long period of cold stratification is required for germination. No seeds germinated when subjected to 8 weeks of cold stratification. When seeds were subjected to 12 weeks of cold stratification followed by constant 68F (20C) temperatures, 33% of the seeds germinated. With 12 weeks of cold stratification followed by alternating 50/68F (10/20C) temperatures, 14% of the seeds germinated (BBG file)

Seeds from 5 sites stored at The Berry Botanic Garden.

Maintain habitat in an undisturbed state (Meinke 1982). Mowing, hand removal of shrubs and trees, and prescribed burning to prevent encroaching shrubs and weedy species. Concurrent monitoring in order to assess the effectiveness of such techniques (Finley and Ingersoll 1994). Evaluate methods of controlling Phalaris arundinacea (reed canary grass) and implement effective measures (Finley and Ingersoll 1994).

Collect and store seeds from known populations. Determine optimum germination requirements. Determine propagation and reintroduction protocols.