Cornus sessilis Torr. — Blackfruit cornelian-cherry dogwood

Introduction

Blackfruit cornelian-cherry dogwood is the western North American outlier of the Macrocarpium clade. It is a deciduous shrub or small tree of moist ravines, stream banks, and cool forested slopes from southern Oregon into northern California. Unlike the red fruits typical of most cornelian cherries, its drupes mature dark purple to black (Flora of North America Editorial Committee 2016; Deasy et al. 2026).

The species is evolutionarily important because its geography and chromosome number set it apart from the Eurasian core of the clade. Earlier phylogenetic work recovered C. sessilis as an early-diverging cornelian cherry, and modern phylogenomics confirms it within Macrocarpium while showing that the exact ordering of sessilis and the African C. volkensii can vary among genomic datasets (Xiang et al. 2005; Du et al. 2023). Its reported chromosome number, 2n = 20, also differs from the 2n = 18 commonly reported for several Eurasian cornelian cherries.

Tree TSAR accepts the species without infraspecific taxa. Its two familiar segregate-generic combinations are straightforward homotypic synonyms and illustrate how its unusual morphology once encouraged placement outside the cornelian-cherry core.

Horticultural and Agricultural Uses

Cornus sessilis remains uncommon in general horticulture but can make an attractive native shrub or small tree where its ecological requirements are met. The species is best suited to moist, well-drained soils, streamside or woodland-edge conditions, and climates broadly comparable with its Pacific-coast native range. Trees and Shrubs Online places it approximately in USDA Zones 7–10 and RHS H5 (Deasy et al. 2026).

The dark fruits and early yellow flowers distinguish it from many other western North American dogwoods. Its value is primarily ornamental, ecological, and botanical rather than agricultural. For native-plant collections, provenance is useful because the range is geographically compact and populations occupy a relatively narrow regional climate envelope.

Conservation Concerns

Cornus sessilis is assessed as Least Concern by the IUCN, and Kew’s automated risk model likewise predicts it as not threatened (Royal Botanic Gardens, Kew 2026). Its global range is nevertheless much smaller than that of C. mas or C. chinensis, so the Least Concern category should be understood as a current extinction-risk assessment rather than evidence that all local populations are secure.

Riparian and ravine habitats can be locally vulnerable to altered hydrology, wildfire, invasive plants, road work, and climate-driven shifts in streamflow. Because the species is a geographically isolated lineage within Macrocarpium, maintaining multiple wild populations preserves evolutionary history that cannot be replaced by the Eurasian members of the clade.

Additional Information

iNaturalist (opens in a new tab) — Direct taxon page with community observations.
Trees and Shrubs Online (opens in a new tab) — Detailed species account and cultivation notes.
Plants of the World Online (opens in a new tab) — Accepted backbone, distribution, extinction-risk prediction, and IUCN status.
IUCN Red List (opens in a new tab) — Global Least Concern assessment.

References and Further Reading

Deasy M, Crowley D, Aldridge J, Chişu R (2026) Cornus sessilis. Trees and Shrubs Online. https://www.treesandshrubsonline.org/articles/cornus/cornus-sessilis/ (opens in a new tab)

Du Z-Y, Xiang Q-Y, Cheng J, Zhou W, Wang Q-F, Soltis DE, Soltis PS (2023) An updated phylogeny, biogeography, and PhyloCode-based classification of Cornaceae based on three sets of genomic data. American Journal of Botany 110(2): e16116. https://doi.org/10.1002/ajb2.16116 (opens in a new tab)

Flora of North America Editorial Committee (2016) Cornus subg. Cornus. In: Flora of North America North of Mexico 12. Oxford University Press, New York & Oxford. https://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=108042 (opens in a new tab)

Royal Botanic Gardens, Kew (2026) Cornus sessilis Torr. Plants of the World Online. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:66176-2 (opens in a new tab)

Xiang Q-Y, Manchester SR, Thomas DT, Zhang W, Fan C (2005) Phylogeny, biogeography, and molecular dating of cornelian cherries (Cornus, Cornaceae): Tracking Tertiary plant migration. Evolution 59(8): 1685–1700. https://doi.org/10.1111/j.0014-3820.2005.tb01818.x (opens in a new tab)